And the same can be said about the digital version. You can use it in ways that you can't use a physical one. Which is better is completely a matter of preference, IMO.

Physical: It's pleasant, intuitive, and the tactile aspects change as you go through the book. Page layout and the feel of flipping through the book can be nice mnemonic devices.

Digital: I can carry a few thousand books on my pocket, put copies on all my devices, do full text searches, follow hyperlinks in the document, etc.