What are the benefits of owning a new iPhone and a new iPod?

If you already have a new iPhone with decent storage, would it benefit you significantly to get an iPod for music? Could you get something less expensive if what you wanted was just a bunch of easily available portable music storage?

We have 2 new Phone 6 phones - and mp3 players. We're both professional classical musicians, and we want All our music when we want it - it is often business, and something we need to listen to for upcoming rehearsals, etc. We have ZEN players - some models now discontinued - and they accept cards as LARGE as you want - and of course, easy to swap out. AND - I want my phone fully charged and ready - no low on battery because I binged on Mahler symphonies. I also fall asleep to my mp3 player - 2-hour shut-off timer.

I don't see a point in having an iPod and an iPhone, at least an iPod Touch. Functionally they're nearly the same minus the phone part. Unless you need two music players for some reason, like to have one in two different places, it's kind of redundant.