I can see that this sounds cool, but I can't quite see the practical use. What's the user intending to do with these? I'm more than happy to look at a map and marvel at it on the iPad, and I'm sure it'll look very glossy, but it would be great if there was a next step to take to add some functionality.
Obviously vtts would work beautifully on the iPad and I can certainly see a market there. Also, custom designed adventure formats for the DM so that they can move through the adventure seemlessly. There must be better ways to organise adventure content on an iPad than just have it flick through a multi-page pdf. All of that would be great, but I'd also take a program that let me zoom and pan a nice large map.
I guess the iPad is big enough to use as a small minis battlemat? It's a little small though.