I interviewed at a print on demand book binding automation shop about five years ago. Naturally one of the topics was the sustainability of paper media on short and long terms. I'll be the first to admit that the interviewer had a vested interest in selling the idea that paper books aren't going away any time soon, but the argument was compelling. As long as children are taught to read on paper books, we will have an…
Beyond this, an actual book gives you a lot more context to help remember things... the feel, shape and even the physically relative position of a given page vs the book as a whole. You lose that when you go digital. You also tend to be tethered to some DRM scheme that can take your books away.