My mileage aired from yours: I would have been happier simply wth pitctures rather than something that hijacked the scrolling and interrupted the flow of reading. Reading on an iPad fwiw.
I actually went and tried it out on an iPad too. I admit it's not as nice an experience - in fact it almost seems buggy, scrolling up past the top of the viewport before the JS notices and suddenly pushes it back down. They could improve that. At least make it less jarring.
