This is a smart move. Students already could do all these things with Amazon, only it required a computer before. By moving the activity to an app Amazon have managed to isolate the student. This means that the student won't be able to compare the buying prices for textbooks and pick the best place to sell it.
As per Amazon's usual, textbooks and other used content sold to Amazon are traded in for gift cards, not money. I, for one, would prefer to sell back to the college bookstore; they always gave me cash.
Students who download this app will also get a year's free membership with Amazon Prime. The student membership doesn't include free instant videos, but it does have the free 2 day shipping.
image by rbglasson