Deeper keels go to windward better than shallow keels. Deeper keels get the ballast lower in the boat, which helps sail carrying ability. Deeper 21 keels find the bottom sooner than shallow keels. The wings supposedly help hydrodynamics. I don't think it's all that great.
Wing keels are good at catching kelp, or anything else floating in the water.
They also stick in the mud better, if that's what you want. To be fair they are a way to get shoal draft and a little stiffness too. They are not more efficient than a straight fin. They do get more weight down low, which helps in sail carrying ability. They may have some hydrodynamic improvement over a straight fin, I don't know.