Am I the only one who found this rather ingenious as well as opportunist/enterprising, something that we at HN are supposed to celebrate and encourage, rather we are complaining about some trivialities?
It's absolutely genius, I just wish Apple had executed their part in it better. They needed to position the holes properly for this usage, and they failed to align them properly.
It's rather disappointing that the case doesn't fit perfectly in that direction. Would've worked better on the iPhone 4-style symmetrical-side design. Pity they dropped that for the 5c.
I could see this being very useful for such applications as synthesizers, mixing apps, DJ consoles, and the like .. heck, any situation where you want the user experience to be channeled in some way. It is often true that swiping a blank-feeling screen, even with pretty lights under it, reduces ones feeling of accuracy. Being able to 'lean on the edges' with your fingertips might make it easier to dodge, bump, scan, and so on, with better accuracy. I'm willing to wager we'll see more of this sort of overlay business soon.
Maybe I'm no fun, but am I the only one who fails to see why this is at all better than a normal, boring Connect Four App? This isn't the correct side board, and for the effort of attaching and un-attaching the case, it only adds a restrictive, small, physical grid which could just as easily have been drawn onto the screen anyway.
A rather sad state of affairs...