While this is (technically) interesting, I don't see it being useful at all on a computer. Page curls are good on devices that can somewhat mimic a page but it really just feels awkward with a mouse or trackpad.
Zoelle from Crocodoc here. I completely agree with your assessment. Our goal here is to explore what's possible from a technical standpoint using SVG — we don't mean to suggest that this page flip interaction should actually be used when reading documents!