Actually the pedal powered device looks very interesting. It uses the largest muscles in the body and is designed to keep the body on centerline so that even the veriest novice is likely to stay upright.
Several kayak fishermen of my acquaintance have bought them in an effort to multitask. It will probably catch on with a fair sized segment of those who boat to catch fish rather than go for the exercise.
I believe it is an innovation by the Hobie company, who made catamarans popular, so there is a history of good engineering there, as well as a company used to do major marketing.