The "Print" button is for printing on your home printer.
Well, Apple came up with their new system couple of days ago ... In the case, that your images will look OK in this kind of ePub format, you can create your books with this tool.
But I read, that iBooks can be huge as 2GB per book - my app has 36,5 MB and contains 78 pages.
People complained about the usual size of iPad magazines - which is approximately 500 MB (with videos). Who is going to download 2 GB?
I am not saying that my solution is the best ... please consider, that you need to prepare your book and it will take a time. And they came up with this new technology three days ago ... I would say in the same time when I released may application