What is the benefit? Lifting foils can be very difficult to make and the boxes have to be very strong. One of the reasons they were problematic on offshore multis for so long is that while changes in buoyancy, CoG and CLR happen comparatively slowly, foils can lose lift in an instant. If you are relying on that lift and it vanishes due to weed or ventilation, you're in big trouble. Those factors don't effect other forms of stability. If you're not reliant on that lift then it's drag and complexity.
Secondly, the evidence from SCHRF stats, which rely on many races, is pretty clear that even changing a cat into a full foiler normally only increases its speed by about 3-4%. The increase in cost is dramatically more than that. There is a bigger performance increase to be gained by fitting a spinnaker, and probably much less overall hassle.
While some craft do gain speed dramatically by going full foiling, they are classes which already have very low drag hulls, high righting moment, high-tech construction, very efficient flat sails of top-end laminates, and extremely good foils. If a design doesn't have such things it struggles to foil and is held back by aero drag and other factors when foiling.
