When I complain about current e-ink book replacements, the problems are the ways in which it fails to act like a real book. For example, it's still slow/awkward

When I complain about current e-ink book replacements, the problems are the ways in which it fails to act like a real book. For example, it's still slow/awkward to jump back and forth between different pages, e.g. when a definition in a list 20 pages back is important for understanding some piece of reasoning. But for something like this, the tiny amount of text visible at a time would make things far worse!