You currently have a Download using cellular toggle. A Stream using cellular toggle would be much more valuable.
I currently have to remember to enable "Offline mode" every time I leave the house. This is maddening. Further, this stops all internet usage. I can't even search through artists and albums. I don't have any problem using a little mobile data for looking things up—I just want to prevent streaming.
It is bizarre that you would have a toggle for downloading. To download something, you have to explicitly choose to; you really can't just do it by accident. Whereas when playing a song from a given artist, it's not immediately obvious whether it's downloaded or streaming. So one can easily do accidental streaming, which is super frustrating if you pay for data (e.g. with Google Fi).