Correct, a floater suit give you 2 hours of safety from hypothermia and the added protection to keep you from drowning. But
that has too assume that you have solid ice or strong enough ice to pull yourself out of the water, and find shelter to warm up.
I think my main point was the greatest problems with snowmobiles is the time you reliase you have a problem you are in trouble, If you were walking you at least know where you fell in there was safe ice to that point and it was not too far away. Even with an ATV you don't travel too far once you hit very thin ice,
snowmobiles can travel a bit over water before the track hits the point where forward momentom slows to a stop.