Taxonomy upgrade extras
Oddly, it's a failure of modern devices to adapt to electronic content. For books, this means that your reader needs to comply with one or more of these formats: EPUB, Kindle, PDF, Plucker, QiOO Mobile, and Plain Text. (This is based on the file selection for texts from Project Gutenberg.)
But paper adapts fantastically. We have paperback, hardcover, oversize books, pamphlets, large print books, tiny pocket books, spiral bound books, weird font books, picture and board books, smooth glossy photographs, textured pages, braille, deckle edges, ... pretty much any form that paper can take can be used to display print and images.
Can I fit a large format world atlas in your iPad? Not without losing the entire perspective of the area. Sure, you can zoom in with any level of detail or scale or at any angle, but does a 30" map really work better on a 6" x 9" screen?
Digital is restrictive. Ironically, when it comes to sharing, electrons are rigid and paper is fluid.