Something I've been thinking about is that a physical book is a physical artifact, and it's age and authenticity can be verified by treating it as such.

In contrast a digital book has no such marks. It's impossible to tell if it was redacted to hide inconvenient passages, or even completely rewritten or fabricated (which can now easily be done at scale with AI). If the physical book is a primary source then the digital version must be considered a secondary source: A potentially biased retelling.

For this reason, a digital book can never be a perfect substitute for the physical book it was created from.