You can even do that without iTunes if you pay $25 a year for iTunes Match.
My original comment was about iTunes on desktop, although the mobile version is also confusing and counter-intuitive, but much less buggy.
I never knew exactly what type of catastrophe would happen to my iPhone when it "synced" with iTunes.
I was responding to this.
In addition, it's terribly buggy. Some things just go wrong from time to time with no apparent reason, and without non-cumbersome ways to recover from. There's lots of issues in the Apple support forums where the answer is just 'yeah, this sometimes happens, you'll have to delete this or that and re-add it'.
Movies was not a good idea. Apps was too far. Music (the subscription service) was stupid. Then they forced UI changes on the old/working stuff because of the new garbage.
I really hope the low level rumors that a rewrite/breakup is happening are true.
iTunes WAS great.