I mostly use youtube-dl for archival of public videos (predominantly some educational material and sometimes rare old tunes of performers passed away many years ago). I do that, because somehow youtube has become the de-facto storage for such material (i.e. people don't host it on their own webistes), yet often some videos/playlists disappear. This is quite annoying, because as you said I have no control on the availability of said content. To me it feels like e.g. someone accidentally or intentionally deleted all Feynman lectures from planet earth as if they never existed. So I as well ask my self what the agenda of the plaintiff may actually be and which of their short and long term interests are being harmed. One hypothesis is that there is increased migration of videos from youtube to other platforms and Youtube wants to diminish that, however they don't want to take the PR negatives for suing youtube-dl, hence somehow encourage the music industry to do this dirty job instead (the latter already has a big track record).