as an avid waterskier as well i have a problem using waterski gloves because of that added support..waterski gloves are purpose built to help you "lock in" with the bar and hold on as it tries to rip itself out of your hands at every turn.. the reason the wrist is not as flexible is in order to turn your entire forearm into a "bar" with the only weak point being your fingers..think of it, ther isnt much wrist movement on a slalom waterski its all straight pull stuff.
i have found this doesnt translate well to using a monving handlebar, specially when you consider the ever changing position of body, arm, weight distribution.
so yes, they are by far the most resiliant gloves to palm tears and abuse in the grip department but personally i hate them for jetski use..
another perfect example is this...i'd never dream of using my street bike track gloves on a dirtbike..again no freedom of movement in the writst, not like a dirbike glove.
in the end..its a personal preference thing i guess..i've also done the cheapy "mechanics" gloves, they blow apart but cost next to nothing in home hardware ;-) mind you no warmth factor there.