I wanted to use it back in the day, but most instances didn't load. Even less often then regular Piped for me. I'd imagine that this wouldn't be particularly improved now that YouTube's doing their whole "Sign in to confirm you're not a bot" spiel
Note that SM64 (and OoT, but I don't think that's on Android yet) are special cases. These have been reverse engineered by the community to the point that they've manually decompiled the entire game, and then separately ported to modern platforms. The project in the OP is different, as it's made for games that don't have this effort behind them
The YouTube app could finally get a sleep timer (APK teardown) ( www.androidauthority.com )
How to port any N64 game to the PC in record time ( arstechnica.com )