I think the mark was missed. If they are buoyant as well as waterproof as stated, then a more fit water use might be rafting.
So what about an SUP [with an internal frame of course]?
The other interesting aspect mentioned is that it fruits as you paddle along! [prob. fresh water tho', rats] - a natural food supply!! or I wonder if we bring a brick as a 'paddle float' along that then produces another veggie garnish for the pot?