I am not doubting that the nano kite rides well.
Problem with this kite seems to be that if you swim towards it or let the lines go slack for a moment while relaunching, it'll fly off the water upside down. If you don't then baby it it'll turn into a pretzel, invert, and flip through the lines and land face down forcing you to swim in to sort it all out.
I think something in the bridles are not correct in the design.