True, or how are you going to read the back side, which sums up the story? When i'm in the bookstore, i'd take a lot of close looks, which wouldnt be possible with a thing such as a book-vending machine. Maybe they thought of something to solve those problems, would be nice.
Perhaps a small screen that shows the front, back and maybe a free chapter of each offered book. But then some people would stand there hogging it and not letting others get access to it, so the design would have to change to let more than one person use the machine at a time.