Its a smart use of what is already there on the camera.
Much smarter than the complication that is the patented Nikon electronic AA filter (which is still just a patent).
Its a good option to have despite all the claims that it may be just marketing gimmick.
Just a year ago, ppl here were bring up grand theories on how the lack of an AA filter was the wrong move and turning them away from a K5IIs.
Now, I'm happy to see those theorists eat their words. (but I'm sure they will find another reason not to buy and stick to their 'best' K200; K20)
I don't even think Pentax spent much time developing it other than software and testing. (which takes effort and time of course)