I’ve been testing Apple Music recently and I discovered that it still supports uploading local files to iCloud Music Library. The interface of Music app is indeed somewhat atrocious, but look:
It integrates music that isn’t available on any streaming platform with all my streaming albums and playlists! And it gets better: playlists can contain both music from my files and streams. 😮➡️💥
As far as I can tell, no other streaming service can do that.