Adding another screen to an e-reader makes perfect sense on paper; after all, who doesn't want to be able to read an e-book the way you read a real book, with two pages visible at all times? In practice, I'm not so sure; personally I've always preferred a single page view in all the applications (various comic readers, Adobe Acrobat, etc) that offered me the choice. But who cares - if you don't like the double page view, you can just use the extra screen real estate for something else: browsing the web, tweeting, updating your blog; the possibilities are endless.
Asus' e-reader, which will also fall under the company's successful Eee line of products, will probably cost around £100 ($163), which would make it one of the cheapest such devices on the market. However, it's possible that we'll see several versions (just try to count all the versions of the Eee netbook, and you'll get the general idea about Asus' strategy when it comes to these things), with the more expensive version of the device adding support for 3G and more storage.