Creating an eBook that looks good on the current cohort of popular devices and platforms isn’t trivial. So there’s a cost to production (and a temporal aspect to shifting standards)

There are non-trivial implications associating a digital resource with the dynamics of physical ownership.

What happens when you sell or give away the physical book?

What happens when a library lends out the book?

Answers can be contrived but the concerns sufficiently inhibit wide adoptions of this pattern.