For reading a new book, the physical form can be replaced by e-reader without problem. But just in case, if you reread a book 20 years later. You may found the

For reading a new book, the physical form can be replaced by e-reader without problem. But just in case, if you reread a book 20 years later. You may found the margin notes you left 20 years ago "romantic". Of course probably most books don't deserve reread every 20 years. I don't have any notes that I kept on computer 20 years ago, they are either lost in disk crash or server meltdown. I still have some note books from then.