Can't remove the battery, and if the power button is part of the GUI and not a actual button seems like it could lead to some problems in theory unless they engineered a way around it...
Otherwise this seems cool. Another pic had the F1, F2 keys, etc so probably would be a way to switch between them for apps that need the F Keys. Will be interested in learning more about this.
Having the functionality shown on the keys would help.
Also Apple is probably trying to create something new to get people to buy the hardware, that's how it works. Apple does try harder than most to make their features actually useful though.