I've never really understood why Amazon has two self-publishing systems: one for e-books, and another for printed books. Having two systems doesn't exactly double the workload, but it doubles the amount to think about, and adds to the number of hoops you have to leap through.

Well, those days could be over soon because Amazon has launched a trial version of a paperback publishing tool within KDP, its e-book publishing tool.

There's some more information on this initiative here: Amazon paperback printing.