A few years ago they forbid apps on the Play Store from having background playback for YouTube, in anticipation of the release of YouTube Red, which would offer it as a paid feature.
I would like to so much. Not for the comfort features (I got all of these already with mpv and youtube-dl), but for the feeling of not ripping them off when blocking ads, and in part also for the original programming (esp. Mind Field).
But, as the sibling says, Youtube Red is limited to a few countries. From what I've heard, it's not in Germany because they cannot figure out licensing with the music industry. I find this utterly stupid, because music videos is precisely the part that does not interest me at all about Red.