I use Spotify on iPhone when I want to share stuff/playlists with more people, but the app is pretty terrible.
Dunno if these essential features are locked behind Premium, but : can't modify the order of the songs in the playlist, can't modify the cover, can't modify the description. Browsing is also clunky : unless I'm missing something, you can't just look up an album and put songs directly from the album page in a playlist? Always have to look up the individual song to get the "Add to playlist" button.
I don't know how the average Spotify user uses the app, but I feel like it's not intuitive at all the second you want to do more than just listening to automated playlists.
Apple Music is just way simpler (with more options), and their front page with new releases etc... is not as messy as Spotify's.