For me the advantage is simplicity. I pick up the book and I read it. No matter where or when, I know I can read it. If the book gets damaged, I pick up another book, I don't mind. The problem with digital books is that I need 3 different things working together: 1) a (charged) reading device, 2) corresponding software, 3) the actual digital book.

So the reading device can be put in unmaintained mode any time by the company who sells it. That sucks. Same goes for the corresponding software, although in this case I have more flexibility sometimes (i.e., I can install some open source software... but that's a hassle in itself). As per the actual digital book, don't get me started with DRM. One can pirate books, though, but then some people have ethical considerations.

I typically buy second-hand books. It's the best deal for me because I don't have the feeling to be super protective with them, and they are very cheap.