It requires a data connection.

I’ve disabled iTunes Match / Cloud on my iOS devices. The stream never works. I have very weak 3G everywhere I go and Spotify, Pandora, none of these work. It’s my fault for living out in the woods. I’m going to give Apple Music a go but I’ll probably only be able to use it while on WiFi (work & home). There’s a reason I have 128GB iPhone and iPad. Each have half of my music library on them and my 160GB iPod Classic has my most played music and I get by with those. Cloud anything just doesn’t work for me. 

The thing is, I don’t see any reviewers mentioning this. I guess everyone but me has 4G / LTE everywhere?