Marc, the only time I used a float boat was when I rented one at Bridgeport Reservoir. It was blowing quite hard that day, and I couldn't get anywhere with flippers, and I was really fighting the wind when rowing.
The main use of these boats in northern California is to float down a river, casting a fly on the way. Then use the oars to get to shore at a take-out point, and hope your ride is there to take you back upstream to your car,