Mine is that YouTube might be wanting to get rid of the loop feature. At least on the app, they moved it from being just a click or two away and hid it under "additional settings", which to me is kinda bonkers. I'm one of those who somewhat often listens to songs a couple of times and probably has a high threshold for doing that. So, if it weren't for the invention of earphones, I'm sure I would've drove a lot of people nuts lol.
Though, I'm afraid by them putting it more out of sight, they are slowly trying to either get rid of it or add it to their subscription program.