I quickly saw that infomercial recently. It reminded me of Slow and Heavy workouts. Your right though, you could do the movments on the floor, but that contraption added resistance.
I was really surprised to hear about that too. It reminded me of some of the equipment Kathy Smith hawked a few years ago. I think instructors should think very carefully before putting their names on equipment - especially when you can get results without spending extra money on equipment you don't need.
I recently saw that infomercial too. Personally, I never buy gadgets like that. I get all the ab work I can handle from Cathe's tapes!! I would rather do good old-fashioned crunches and core work than use some gadget, but I guess it's personal taste.