2020 skews results. Some funds have done way better than their long term performance would suggest, LLSCX has done remarkably worse (99th percentile of mid cap blend category).
Looking instead at 1/1/2010 through 1/1/2020, LLSCX has done okay. Not an endorsement or a commentary on its investments, but rather a suggestion to look at more than one snapshot in time. Especially given that the outsized impact of the 2020 market effectively transforms some "long term" figures into "what have you done for me lately" pictures.
Here's a chart over that timeframe comparing LLSCX, R2K (its stated benchmark), midcap blend (its M* category since 2011), and small cap value (it claims to buy small cap companies, and Longleaf generally claims to be a value family). It just edged out R2K (210% cumulative return vs. 206% for R2K), and did better against the MCB and SCV category averages.
M* comparison chart
If you don't like looking at charts (personally I prefer to read numbers), the LLSCX summary prospectus says that the fund's average return over the past ten years was 11.98% vs 11.83 for the R2K. That's 2010-2019.
Why bother? Lots of better funds out there.
Can't argue with that :-)

[Did not see David's post above as I was constructing this one.]
LewisBraham:
Of course I am not sure, but I believe that it is (more or less) a first.
Did a Google search that came up only with one story from 2008 [!]:

Claymore Advisors announced that the shareholders of Claymore/Raymond James SB-1 Equity Fund (RYJ) have approved the [closed-end] fund’s reorganization into an ETF format.

(Ignoring Vanguard's patented mutual fund/ETF structure.)
These 2019 stories suggest that this could be a first.

https://www.etf.com/sections/features-and-news/how-mutual-funds-convert-etfs
https://www.bbh.com/en-us/insights/making-the-switch--turning-a-mutual-fund-into-an-exchange-traded-fund-38254
https://www.thompsonhine.com/publications/converting-a-mutual-fund-to-an-etf-key-considerations

The last (7-15-2019) from the Thompson Hine law firm, states:

To date, no mutual fund has been converted into an ETF. Such a conversion raises regulatory and operational issues, none of which are insurmountable.

So, think it is probably a first.
(Will you let us know what you discover?)
-----------------------------------------------
May 30 Update: See LewisBraham's May 28 post below.

I have been in and now out of Longleaf funds for decades. I finally gave up. While their reports are wonderfully detailed, and they make compelling arguments for all of their positions, the market seldom agrees.
I think they make some disastrous mistakes over the years, and stuck with large positions that were cheap and stayed cheaper or got cheaper.
Neither LLSCX or LLPFX have beaten their benchmark over the last decade. 11% of LLSCX is in Century Link which is down 35% since they first bought it. While CTL owns a large chunk of the internet backbone, it is loosing revenue quickly.
Why bother? Lots of better funds out there.

Too much bad news still out there. I'm slowly selling things as market rises to build cash. I think we're going to have a lot more businesses going south this summer. We're starting to see small businesses locally (WA state) announce going out of business sales. I think that will continue. And big companies like JC Penney and Hertz announced this week too. I think that trend will continue as so many businesses are leveraged to the hilt (as the MBA degree folks think that is the best way to do things).
So right now I'm taking profits and building cash. I've made a bunch of money in this rebound with QQQ although I sold my last of that this week. I'm about 50% stocks now where I'm usually more like 75. Still about 10% down for the year; that happens but I don't want to take a big drop.

May 23rd Episode:

I also wish to thank @Puddnhead for all the informative and entertaining B/ S threads over the years. I suspect that’s a favorite read for many who don’t actively participate.
@Mark - Your Lyn Alden Schwartzer article would also fit under the “What The Hell is The Stock Market Doing?” thread: https://www.mutualfundobserver.com/discuss/discussion/56135/what-the-hell-is-the-stock-market-doing-cullen-roche

Lyn Alden Schwartzer's May 19 article, "First Liquidity, Then Solvency," is a brief, detailed and chart-laden description of today's economy and market.
"Does it get better from here, or is this a big fake-out for another round of selling as we move deeper into this year? ...
"The next several years are likely to be challenging for many companies with weak balance sheets, so make sure you know what you own.
"...the top 5 mega-cap stocks have held up the major American stock market indices like Atlas holding up the world, and reached levels of concentration not seen in nearly four decades."
"...policymakers around the world can't afford to let a massive deflationary economic collapse occur, and for millions and millions of people to be unable to afford the necessities of life and for half of large companies to go out of business, so they will be forced to keep the stimulus taps open, funded with printed money, with a willingness to devalue currency to avoid the worst case economic scenario."

Roubini again
https://nymag.com/intelligencer/2020/05/why-the-economy-is-headed-for-a-post-coronavirus-depression-nouriel-roubini.html

LG is where it's at for true growth.

Yeah. Trying to see any args against all VONG all the time; slicing and comparing past subsample periods and all that.
VONG started later than the awful late summer of 08 and on to the April 2010 recovery, but taking TRBCX as a sort-of proxy (it performs slightly better than VONG, and yes, has holdings in the low hundreds as opposed to the low 500s), it is only from Aug 08 to Feb 09 that LG underperforms SP500, and by a nontrivial gap, like 10%. But then back to even, after that brutal half-year.

News article concerning reopening:
https://www.advisorperspectives.com/articles/2020/05/22/southeastern-the-exceptional-opportunity-in-small-cap-value?topic=energy
Southeastern Asset Management excerpt concerning LLSCX reopening:
We designed this reopening in a thoughtful way. We are only targeting $2.5 billion of AUM. If we get there quicker with a performance bounce-back, that's great. We'll close again. We've shown over the years that we focus on doing the right thing for those clients who are already with us.

Although it is more common in closed-end funds, return of capital also occurs in open-end ones:
https://investmentnews.com/funds-featuring-managed-payouts-off-to-rocky-start-19815
https://investornews.vanguard/updated-distribution-estimates-for-vanguard-managed-payout-fund-2/
https://investor.vanguard.com/mutual-funds/profile/distributions/vgsix

Managed payout funds are explicitly designed to pay steady amounts, like annuities, except that they adjust their payouts periodically, typically annually. It's a nearly hopeless task, especially in a low and declining interest rate environment. Hence their return of capital. At least they are upfront about it.
Vanguard essentially conceded how difficult this is when it merged three managed payout funds into one. It gave up the ghost in February, when it announced that it was changing the div schedule on VPGDX from monthly to annual starting at the end of this month (May).
https://www.barrons.com/articles/vanguard-throws-in-the-towel-on-its-managed-payout-fund-51582939988
REIT funds are another odd sort of mutual fund. They invest in REITs which often make return of capital distributions. I'd guess that funds holding REITs just pass this through but I've never looked closely at how REIT funds handle distributions.

REITs depreciate their assets, which reduces net income. But because depreciation is a non-cash charge (and may not reflect the actual change in value of a REIT's property portfolio), the REIT's cash flow is usually higher than its taxable income. The difference is classified as ROC and is included in the distribution to unitholders.

https://www.theglobeandmail.com/globe-investor/investor-education/learning-to-roll-with-roc-can-pay-off/article24704378/
When funds make return of capital payments they file IRS Form 8937. Outside of REIT funds and managed payout funds, such payments should be pretty rare. You can see that in Vanguard's list of 8937 filings:
https://personal.vanguard.com/us/insights/taxcenter/form_8937
Likewise, infrequent for American Funds (the July 2016 entries are for fund reorgs, not ROC)
https://www.capitalgroup.com/individual/service-and-support/tax-center/form8937.html
T. Rowe Price seems to have around 3-4 funds each year with ROC
https://www.troweprice.com/personal-investing/planning-and-research/tax-planning/dividend-distributions/corporate-actions.html
Pimco seems to have around a dozen or so funds each year with ROC
https://www.pimco.com/en-us/resources/tax-center

I'm just pissed my conservative income portfolio in my IRA is doing worse than S&P 500. I guess I don't know what it means to be conservative. It would seem I should have been in LG funds

https://www.sec.gov/Archives/edgar/data/919160/000139834420011445/fp0054046_497.htm
497 1 fp0054046_497.htm
Guinness Atkinson Funds
Guinness Atkinson Asia Pacific Dividend Builder Fund (GAADX)
Guinness Atkinson Dividend Builder Fund (GAINX)
Supplement dated May 22, 2020 to the Prospectus and Statement of Additional Information dated May 1, 2020 and Summary Prospectus dated May 5, 2020
This supplement provides new and additional information beyond that contained in the Prospectus and Statement of Additional Information (“SAI”) and should be retained and read in conjunction with the Prospectus and SAI.
* * *
On May 14, 2020, the Board of Trustees of the Guinness Atkinson Funds (the “Trust”) approved the reorganizations of Guinness Atkinson Asia Pacific Dividend Builder Fund into SmartETFs Asia Pacific Dividend Builder ETF, and Guinness Atkinson Dividend Builder Fund into SmartETFs Dividend Builder ETF. There will be no change in investment objective, strategies or portfolio management.
A Prospectus/Information Statement with respect to the reorganizations will be mailed before the consummation of the reorganization to holders of each fund’s shares as of the record date.

RPSIX is a bond fund, but with 15% in stocks. Monthly pay-outs. Yield right now is at 3.51%.

Although it is more common in closed-end funds, return of capital also occurs in open-end ones:
https://investmentnews.com/funds-featuring-managed-payouts-off-to-rocky-start-19815
https://investornews.vanguard/updated-distribution-estimates-for-vanguard-managed-payout-fund-2/
https://investor.vanguard.com/mutual-funds/profile/distributions/vgsix

https://www.axios.com/stock-market-speculation-coronavirus-8648eb3d-34b6-4457-9d6f-7dcbf1ad69bb.html
The stock market's speculative frenzy
Never has the stock market seen so much gambling. Volume is at record highs, with individual stocks and the market as a whole feeling almost manic. More people than ever are betting more money than ever on which way stocks will move, in a frenzy that feels more like a casino than a safe place for long-term capital appreciation.
In other words many of us maybe playing Russian roulette with our investment monies...

My all equity dividend paying funds that are found in the growth and income area of my portfolio follow. They are for my domestic equity sleeve: FDSAX with a yield of 3.95% ... IDIVX with a yield of 3.96% ... INUTX with a yield of 3.41% ... and, SVAAX with a yield of 4.44%. In my global equity sleeve the funds held are CWGIX with a yield of 1.92% ... DEQAX with a yield of 2.58% ... DWGAX with a yield of 2.18% ... and, EADIX with a yield of 3.76%.
The dividends paid by the above funds, by in large, were coded as qualified dividends on my broker provided 1099.
I have other funds that are good dividend payers but I consider them to be of the hybrid type.

Thanks for your list @Old_Skeet. A few of your funds are mentioned here (VHYAX (VYM) & VDADX (VIG) seem better tickers than the two mentioned in article):
best-8-funds-regular-dividend-income

You can’t fake, manipulate or fudge a dividend payment by hiring a talented CPA.
No cash on hand? Pay a stock dividend, or perhaps better, pay it in scrip (IOUs).
https://www.accountingtools.com/articles/2017/5/16/types-of-dividends
No retained earnings? No problem. Pay a nimble dividend out of current earnings.

A few states—significantly, Delaware is one of them—permit dividends to be paid out of the net of current earnings and those of the immediately preceding year, both years taken as a single period, even if the balance sheet shows a negative earned surplus. Such dividends are known as nimble dividends.

https://saylordotorg.github.io/text_business-law-and-the-legal-environment-v1.0-a/s47-05-dividends.html
Lewis already addressed fudging at the fund level.
Though I do agree that you don't need an especially talented CPA for these maneuvers. This is all just Corporations 101.

https://www.nytimes.com/reuters/2020/05/22/business/22reuters-mexico-pemex-bonds-analysis.html
Why Bond Investors Are Willing to Bet on Money-Losing Pemex After Oil Price Crash
By Reuters
May 22, 2020
Updated 8:23 a.m. ET
MEXICO CITY/NEW YORK — Mexico's state-owned oil company Petroleos Mexicanos has seen investor sentiment improve in recent weeks despite sky-high debts, a slump in demand and no clear direction about how the government will turn the money-losing driller around....
Price 89cents...high 8.25% ytm ..very interesting vehicle to look at
Cusip
71654QCT7

My all equity dividend paying funds that are found in the growth and income area of my portfolio follow. They are for my domestic equity sleeve: FDSAX with a yield of 3.95% ... IDIVX with a yield of 3.96% ... INUTX with a yield of 3.41% ... and, SVAAX with a yield of 4.44%. In my global equity sleeve the funds held are CWGIX with a yield of 1.92% ... DEQAX with a yield of 2.58% ... DWGAX with a yield of 2.18% ... and, EADIX with a yield of 3.76%.
The dividends paid by the above funds, by in large, were coded as qualified dividends on my 1099. The difference between qualified and ordinary dividends is quite substantial when the time comes to pay taxes. As the name implies, ordinary dividends are taxed as ordinary income, while qualified dividends are taxed at a lower rate.
I have other funds that are good dividend payers with most of them of the being hybrid type which pay out mostly ordinary dividends with some of the dividends being coded as qualified.
Overall, qualified dividends accounted for about 10% of my income with ordinary dividends accounting for 23%. With this, dividends account for about a third of my income. This is one of my reasons for adding to my qualified paying dividend funds during the recent stock market swoon and that was to grow the amount of qualified dividends that I receive.
Thus, the qualified dividends payers have become and are a part of my tax management and investing strategy.