Although I wouldn't use one in an area where standard PWCs are available, the design does have possibilities, such as being taken to remote areas where a trailered PWC isn't practical. From a purely design point of view though, there are a few issues I see, namely safety. There is a lot of exposed metal in the steering stalk and the handlebars themselves are, well, handlebars. Anyone who's ever taken a hard impact to the chest on a PWC is looking at those handlebars with horror. Adding a little padding to the stalk would not add significant weight, and it's possible the final product will include such a small safety enhancement. Then there is the question of the breakdown itself. Toting around a hot engine full of fuel in the back of your trunk is unwise at best.
Like any design it isn't perfect, but it may well find a niche in the market. I rather like the idea of taking one in the back of a Jeep up to remote mountain lake.