disclaimer: I am one of two co-founders of U.GG.
Thanks to u/RiotAugust for providing the context. I and the rest of the team obviously don't think U.GG is garbage but I understand the perspective RiotAugust presents. We do our best to gather as much data as we can get, display it and allow the player to draw their own conclusions from the data. The great thing about data is one number can be used to tell multiple stories. For example, the Lt. Gov of Texas (we're based in Austin, TX) can look at 500 deaths in Texas and come to the conclusion that stay at home order is overblown and it is time to re-open Texas, whereas someone else looks at 500 deaths and concludes that the strict stay at home order is exactly why the death toll isn't substantially higher.
People drawing conclusions from a small sample size in my opinion is part of what makes League of Legends fun and keeps the game fresh. A champion designer/game balancer might add that it also makes their work a living hell. At the end of the day I think it's great for everyone when we're all talking about League. It sure as hell is better than talking about Covid.
Edit 1: To explain drawing conclusions for a small sample size, there are situations when the entirety of the sample is "small" like the example RiotAugust gave where maybe a couple people play Ivern at master's+. We display exactly as much data as we can gather. Like what u/wertache said below, scouring these relatively obscure builds and champions for something op to climb with is a fun and fresh part of the game. If it works, it get's picked up by more players and there is more data, and with the larger sample we get a better understanding of whether the build is truly op or just something a onetrick is able to find success on. When it does work, the meta shifts and the game stays fresh.
Edit 2: Some people are curious why our total matches analyzed is low for patch 10.8. It is low for this patch. A lot of people believe that if it ain't broke don't fix it. I personally believe that if we aren't constantly striving to improve our systems, someone else will eventually come along with nextleaguesite.gg and I'll be out of a job. We built U.GG on a fundamental belief in speed. Speed in how quickly we can grab data from Riot's API within the limits of their rate limits, how quickly we can aggregate the data from our databases, and how quickly we can serve the data to player's around the world. For patch 10.8, we made a change to our aggregation algo and we missed an edge case bug that, one week into the patch, compiled an "empty" file that resulted in our tier list and some builds resetting to 0 games analyzed. We don't lie at U.GG so we fixed the bug and restarted mid patch. The matches analyzed reflects exactly as much data as we have. This bug is fixed. I can't guarantee that we won't have other bugs that cause issues in the future, but I do guarantee that we will continue to work on improving our systems to make it faster.