After fighting a long time to own my music, I have to admit I got tired of maintaining a library, and mostly listen on Spotify these days. But I never liked the library-based model anyway, and so (when still dipping into my own library, and especially when watching movies) prefer an app like VLC that accepts that I might occasionally just want to play a media file without making a library. (Same thing with Books: for some reason, Apple can accept that I might just occasionally want casually to open a PDF in Preview, but finds it impossible to believe I might want to do the same thing with an ePub. I still haven't found a good non-library-based ePub app for macOS; I wind up just using the one that comes with calibre.)
Thank you for the recommendation! Having to sign in is even less appealing to me than being forced to maintain a library, but it's good to have the option.
It's technically no longer even there on macOS, thank God. It was becoming a sort of kitchen-sink dumping place, and I am glad that I can now manage my iPad through Finder (though I still wish I could just treat it like any other bulk-storage device, as I can on Windows, at least it's there). There are apps called "Music.app" and "TV.app", if I want to access my music and videos the Apple way, but I can and do just ignore them if I don't want to use them.
There are probably a multitude of other features that were in the old iTunes app that I never even noticed or have forgotten, but I think that a lot of users who used to be forced into using iTunes on macOS now can avoid both it and its replacements.