Kirk McElhearn walks through the process of sharing files between two AirDrop capable iOS devices. My instinct is to email any files I want to share. I asked Kirk when he would use AirDrop instead of email. His response:
That’s what I used to do. AirDrop is faster for photos or PDFs. It’s just one step less. And if files are too large such as very big PDFs, they might not fit through email. For photo: AirDrop: Tap, tap, tap, done. By email: tap, type address, send, check mail on other device, wait, tap to save, etc.
I found this writeup fascinating and I’m glad to know how this works.
Finally, why can’t you share files between OS X and iOS? This is surprising, since they both have AirDrop. I’d often like to move photos from my iPhone to my Mac more easily than by syncing. And I’d occasionally like to send PDFs to my iPad to read without having to sync or send them by email.