It wouldn't take much more work to add mouse functionality, allow those photos to be flipped over and even sort them into a photo-album type structure. The real work would be build a nice sorting algorithm, something that can sort through the photos in a useful manner, etc.
And yes, I do understand Photosynth does a lot more than that.
No, you clearly do not understand Photosynth. Photosynth does have a "nice sorting algorithm". The way that points are analyzed and sorted and mapped out in space to allow the system to tell that two photos are related, and know how to lay them out in 3D in a plane - YOU have no idea what you are talking about. A lot of people DREAM about ideas like this, I know I have, but to actually code it. Ha. Man, you just have to smarten up and watch the Photosynth technical video interviews, because you clearly don't know what Photosynth's capabilities are.