Over on GitLab, I made a proposal to remove GNOME Music from Core. Not because it is bad in any way, but because I think there shouldn’t be a music player in core.
GNOME Core now has a great application to play single audio files: Decibels. It is not, however, a music player as most people would expect it, as it only plays a single audio file. The problem with a music player is that the way people listen to music varies a lot. This is reflected in the huge collection of GTK4/Adwaita music apps:
There is Amberol for people that want to create a playlist and just play it, and there is Gapless for people that want to organize a big music collection. There is Shortwave for people that want to listen to Internet Radio. There is Plattenalbum for mpd users, and there is Spot for Spotify users. And the list goes on.
From my point of view, playing audio files “provides functionality that is deemed to be essential for the desktop”. But I would argue that beyond that, it is difficult to define what is essential in the area of music, given the wide variety of use cases from playing albums, playlists, radio stations, streaming providers, etc.