I can tell you why I do. I watch more YT than anything else (on my TV), and don't want to watch ads, or play cat and mouse games trying to prevent them. I also listen to a lot of music, and use YT Music. I pay for the family plan, since we all listen to music, and my son and I watch a lot of YT (very different videos on YT however :) )
I get, there's a growing group of people that think everything should be free, but I'm OK paying for something I use a lot, to remove ads. There should, however be more controls for paid users, like controlling whether or not you see creator ads, shorts, etc...
There are android apps (I could side load) on my Nvidia shield, but like I said I don't mind paying for something I use , and use a lot.