> With books, movies, series and music I like to own physically only my personal favorites that I know will use many times.

I don't own many DVDs, but when I see them in my bookshelf they remind of the story the tell, the context when I watched them, and my theories about society, sci-fi, and utopias that those movies inspired.

With books it's even more extreme. I get the physical copy sometimes more to have a physical representation of an idea than to read the book.