Its interesting, like a sort of extension of the fixed gear concept, removing aspects of the bicycles function in order to prevent biomechanical laziness, and get your body working on muscles it doesn't normally use.
I disagree. With fixed gear you can cheat because the rear wheel will push the pedals over for you because of your forward speed (or backwards). With powercranks no such thing exists. The real benefit of fixed gear is that you MUST be pedalling all the time everywhere (unless you take you foot off the pedal).