Danny Heitman points out another benefit to electronic books--Life Without Guilt:
My brother Randy, an avid reader since childhood, has gone for e-books in a big way. He loves their convenience and portability. But as he recently confessed to me, the new electronic format has at least one other advantage: Put simply, my brother is no longer haunted by the physical presence of books he hasn't read.
Like most bibliophiles, Randy still acquires many more titles than he has time to read, but now the neglected texts lie quietly in a digital file, out of sight and out of mind. With traditional books, on the other hand, the guilt of an unread novel, biography or history can linger visibly for a lifetime, the ghost of a good intention never fulfilled.
Book lovers will recognize that sense of guilt that unread books create. Sometimes it almost seems as if they're looking at you asking "Why? Why haven't you read me as promised?". Much easier to have them tucked away out of sight in your Kindle, Nook, or iPad.