I’d rather own my music.

I don't think it's an either/or proposition. Given how cheap storage is nowadays, I'm also used to just have my music collection replicated through my devices and listen locally, but being able to upload that library and share with my friends (and in turn, get access to their library as well) seems like a very nice way to discover more stuff and increase the range of available content, without losing "ownership" of anything. Unlike Spotify or the other streaming services, there is no central entity determining what should be available or not.

(Of course, this doesn't mean that is a good idea to just upload your collection to a Funkwhale instance and make it public for everyone. That will be a very fast to getting kicked out. Or worse, to be receiving a nastygram from some IP lawyer)