I think the apps are nice, but the major enabling technology is multitouch. Which has been around, but just now is making some (marketing) headway.
Coupled with a large screen it is awesome, but I could see this in several applications. Imagine just the simple touchpad on a laptop being multitouch. You could do a lot of the similar photo manipulations with just that, separate from the screen. Or on pda's or large screen phones (like the iphone).
Anyways, could be kinda cool in the future.