Lots of adults today grew up with Pokemon. The first Pokemon games came out globally in 1998 IIRC, so the gaming franchise itself is at least 21 years old, which is basically an adult lol. I wouldn't be surprised if there's a significant crossover between Pokemon fans and crypto users.
It's pretty unfortunate about the fees. It could be because of his low view count, high fees (I mean, the current recommended fee right now for a typical transaction is about a third of his tip total), or a combination of both. Also, did he even include his tipping address in the video itself? I don't see it.