When I buy a printed book, I own the book. I can read the book whenever and where ever I want.
When I buy an eBook, I do not own the book. In order to read the book, I have to hope that some DRM server somewhere will authorize the eBook reader to show me the book I want to read.
I have books on my book shelves that are over 50 years old, and I can still read them fine. Can the same be said about eBooks 50 years from now?
I have a bookshelf, and an ereader. I can only have one of them with me most of the time, and it's not the bookshelf. I love reading, but I'm a slow reader, so it helps if I can squeeze in a few pages here and there wherever I am. Hard to do with a big hardback or with a book you weren't planning to read that day. Between keeping books and reading. read them, I prefer the latter.