Well, I've only landed a helicopter in the water a couple of times, but I have landed airplanes in the water thousands of times. Sure, in the calm conditions shown in the video, water work is straight forward, but once the wind, waves, and an uncertain bottom are factored in, a good outcome is much less certain. I've trained enough floatplane pilots to know that all of them had very unrealistic expectations of the water conditions which could be accepted for a landing. At least floatplanes and flying boat airplanes are decently stable in all directions. I would be very cautious of this helicopter perhaps landing into the waves or swells, then turning for whatsoever reason (including a floating start) and becoming sideways in the waves or swells, and being very much less stable.
And it's one thing to drift into shore in a seaplane, it's different when a rotor is projecting out in all directions. I've had wingtips in the branches many times, no problem. Big problem with rotor, even if not turning.
It looks like an attractive idea, as long as the pilot has very conservative expectations of suitable water conditions, and operating limitations.