This is far from the first time someone has had this idea.
It turns out typing on a virtual keyboard without the physical feedback of the actual keys is a horrible feeling for anyone who's been using regular keyboards for a while.
I'm sure you can find someone with enough geek-spirit to get good at using this but most pragmatic users will get frustrated from having to look up and down to find the keys and mistype while trying to instinctively find the right key.
Furthermore, there is little use as of now for the second screen; unless it uses the tablet recognition system of win7 (which is actually a pretty attractive thought for asian language users), there's little use I can think for this piece of novelty hardware. Quite honestly, I'd rather they put the hardware budget into a better top screen with pivot and multi-touch and better physical keyboard.
While it is by no means an original idea (someone was asking about one just the other day in the comments), it's still one a lot of people really seem to want.
Remember, MSI is calling it an eReader, which means that the primary focus is on using it as a book, not as a nettop, which likely means that readers will be holding it on its side, most of the time. Personally, that's appealing to me, although not having a seamless display means that double-page splashes in comics are out of the picture.
When will someone come out with a full-color ereader/music/video player on a reasonable screen?!