Yes, there absolutely is something unquantifiable about holding a book in your hands and turning the pages. It's a completely different interface with the content. It makes it easy to compare back and forth at random between two different pages. It has weight. It has texture. It has a smell - a newly printed book smells one way, an old book a different way. None of those apply to e-books. For that reason, especially when talking about photography books, the death of the printed book is greatly exaggerated.