Good question. I called and talked to a man at Optibike, the company in the video, and he had some good answers- as I asked the same question, "why not just ride a regular bike?" He (I think his name was Craig) asked me how far I ride a regular bike now, to which I answered "not very far." When asked why, I replied, Because it is not very much fun when you are not in very good shape.
From digging around their website more, they have some interesting data about people riding their bikes LONGER, hence getting a better (long duration) cardio workout that is FUN, which makes you want to keep riding. He equated their motor system to a "human electric hybrid" system that allows you to pedal as much (or as little) as you would like- so I believe there is real potential there for some good exercise.
To make a long story short- I went ahead and ordered an Optibike 800Li (with a heavy duty package because I am heavy!) I figured with the 90 day return policy, if the bike does not work well, I will just send it back. They seem like a nice group of folks (they actually make the bikes in Colorado! Imagine that!!)
I will keep posting my weight loss stats in this thread as I brave some new ground here....
Greg.