you can't copy it and sell it on. But you can share with others. You can even sell the book. It is very convenient to have hundreds or even thousands of books

you can't copy it and sell it on. But you can share with others. You can even sell the book. It is very convenient to have hundreds or even thousands of books in a tiny device, especially for someone who has very little space to keep physical books (and those who move a lot). While nothing can replace physical books, ebook readers are a fairly good compromise. Plus, it is possible to reduce the cost of books (and less dead trees). But we can't share, unless we share the ebook reader device itself :( As with most things, humans will put commerce first, and I don't see this situation changing anytime soon. Amazon has won the ebook reader race and they are likely going to stay there for a while.