That is one of the craziest kite tools I have seen yet. Way cool, although a bit complex.
Having used both a boat and Jet Ski for lake launching (it get's very crowded at times) I prefer a good three person Jet Ski. I have a high performance model (2 person) and it is very unstable although still effective.
The Jet Ski is more maneuverable and does not have many if any surfaces on the underside to catch lines and very few sharp points. Although not traveling over the lines is advised if possible. When traveling with 2 people and a fully inflated 21M kite we were able to travel at about 15MPH going directly into the wind. The TRICK, Hold the kite as you would when walking on land in the upside down position. wind the lines up tight to keep the tips from flapping and tangling the lines. The passenger sits backward holding the kite in there lap.
When launching the Jet Ski or boater holds the leading edge of the kite and progresses upwind to tension the lines and maintain a safe distance from the kiter. Which is what the person on the Jet Ski does once the kite is launched (Run Interference from boats and other Jet Skiers).
When approaching a down kite (in order to flip it into a safe launch position) it is best to com from the downwind edge and grab the leading edge. The Jet Ski works well for this because it has no sharp edges. Once you control the leading edge travel to the edge of the window and release.
We kite on an inland lake approximately 1.5 miles by 3.5 miles with all manner of watercraft (power, sail, row, swim, etc). When winds are light a down kite can be a real problem as no one around here understands the concept of lines under tension causing harm.
As an example of how a Boat/Jet Ski can be very helpful. I had to head of a mesmerized boater who was fixated on my buddy's kite. They were on a collision course and the boat was in my buddy's blind spot. I came zooming at him at top speed waving my arms to get his attention with seconds to spare. My buddy saw him at the last second and steered further away as the boater came to a stop.
If curiosity doesn't kill the kat it might the kiter, at least in Ohio.
Happy and Safe Winds!