I want a radio experience, where some nice person somewhere else (or an algorithm, whatever) picks music for me. Bonus points if they don't come on after every song to tell me all about whatever. I'm not worried about the cost or inconvenience of using cellular data services to stream music, that's the primary reason I have a data plan.

I use a curated streaming service, but I can see the appeal of Spotify, because thanks to the mandatory licensing regime, they can literally stream any released music in a radio context; and having access to everything is amazing. When Launchcast was a thing, it's recommendation engine was pretty great, although they lacked depth in the genre's I want to listen to; I strongly suspect Spotify does too.