As it stands, tapping the Kindle icon on that external screen simply launches the standard Windows Kindle app, and there doesn't appear to be a way to tweak things so that a tap on the side of a page flips the book to the next one. It's fine if all you plan to do is click through a couple of pages, but I couldn't imagine getting through a whole book like this. And since this is, by Lenovo's admission, a computer meant for business customers, it's even harder to imagine that its target audience would even bother.
If some of these features sound a little... shall we say, half-baked, well, you're not wrong. For what it's worth, Lenovo doesn't really imagine people shelling out north of a thousand dollars for a laptop because of this additional display. Instead, it's more of a bonus. If people figure out ways to improve their workflows because of it, great! If not, well, they still have a perfectly fine PC with a reasonable price tag.
Beyond that, the ThinkBook Plus is just one of those delightfully weird machines that so often appear at CES. At best, it's an example of blue-sky thinking that could lead Lenovo to rethink what its computers should be capable of. And at worst? Well, it'll be a pretty good conversation starter at that upcoming chamber of commerce meeting.