Having grown up in a religious household and handled many a "wafer-paper" Bible, I have to say, I would NOT want to read a regular book printed on that paper. The pages are exceedingly fragile and have to be turned with care and delicacy or they will tear, and gods help you if you spill food/drink on the page -- you'll ruin the text entirely.
The format works well for religious tomes because usually you don't read those bad boys at breakneck speed and you tend to keep them well away from damage-potentials like wind, rain, food, drink, enraged cats, etc. But for "regular" books, I have to think they'd have to be marketed as "disposables", and is there really a market for that??
Anyway, I would think most eReaders would tell you that the value lies in having their entire library and/or bookstore a click away. These don't offer a competition to that; and they won't entice the traditionalists who don't want to abandon their favorite formats. So this seems DOA IMHO, but maybe I'm just skeptical.
