It's a mouse trap... different engineers and manufacturer's will probably argue it. The wet clutch keeps the CVT drive belt under tension at all times so it is smoother and allows engine breaking in an easier smoother way than a grab-&-go belt setup. The wet clutch is a maintenance item and sooner or later you will have to spend several hundred dollars to replace. the sooner depends on driving style. The G&G belts are easier to replace and most units are designed to easily do those in the field. Most belts on wet clutch units I have seen are much more difficult to replace, but Yamaha for one gives a 10 year warranty on their units so they recognize it is not frequently necessary. It seems to me that the wet clutch units are not quite ready to accommodate the higher horsepower that is coming with bigger engines and the turbos, but who knows what the future holds. The wet clutch also appears to take significant driveline shock out of the equation, so that maybe that is a big positive for axles and diffs and u-joints. There are some higher HP motorcycles that have wet clutches but the weight of a motorcycle and the torque required to be transferred is certainly a different animal from a SxS. Just my view, ready to hear factors to learn, but not argue lol. Others will probably offer significant factors.
Edit: It appears it is probably cheaper to manufacture a G&G system and the systems have been developed to provide better engine braking and tuning now than they used to.