He's a ballhawk. He goes to games, arrives early for batting practice, and his goal is to get as many balls as he can. He'll catch ones that are hit, thrown, not caught by others, and use devices to pick unreachable ones out. He stays for the game as well obviously, but his footage prominence is about the balls he can snag.
His streak was something like 1000+ games having gotten a ball hit or thrown to him, whether in BP or in game, and has retrieved over 10,000 baseballs in MLB games in total. He was the one who famously caught two home run balls at Coors Field in the same game (maybe the same inning?).
His videos
are fun to watch, though. He shows many intricacies of stadiums that I don't get to see if I haven't been there, especially in the outfield area. It's cool when he calls out to guys like Mike Trout and he'll go to him and say what's up. I think he's perhaps outgrown what he started off as at the time, kind of like Green Day trying to look like how they once did 30 years ago lol, but I think any so-called notoriety that he has adds to the flair of some of his videos as well.
Once again though, I haven't seen any of his videos in over a year, but I think it's overall pretty harmless and YouTube is a good platform for him to showcase it on.