To you and all the others going on about data... They are talking about iTunes downloads where you purchase an m4a file. IF (big IF) they stopped selling them as speculated may happen one day, I'm pretty sure that has no impact on the ability that Apple Music, and other streaming services like Spotify have, which is to download songs from their library for offline listening.I have tried streaming at home and was left with an overwhelming "meh". I will never stream music (or anything else) with my iPhone because there is no way I am running the risk of going over my data allotment.
Yes, there is still a huge difference between the traditional model and this- you're tied to paying a subscription (cancel and you lose the music), you don't get a file that you can take elsewhere, you can only listen to it in the service's app, etc. etc.
BUT, if your only concern is really only data usage, then you could use Apple Music with the same data you use for iTunes. Find the tracks you want, download them for offline listening, job done. You just have the added option of also streaming music you don't have saved offline- but that's your choice.