Depends. I find under hard braking, it improves a little, but not all that much. It's not a large pad. And if installed correctly, while riding, it is just slightly above the knees when you are riding/braking. It is designed to give you traction when you lock your knee into the side of the tank - which means when you're shifted over and hanging a bit off you lock the opposite knee /into/ the tank. Locking the knee into the tank when done properly is usually raising your calf to wedge the knee into the side of the tank (which is why the stomp grip pad is just a bit higher than where your knee would be while normally riding). The stomp grip then gives you better traction right along the inner thigh above the knee and to the tank.
So yes, it helps when you're hanging off or shifted over. But for braking it may help a little but if properly applied - maybe not. As it should be applied probably right under the ridge of the tank and toward the middle. But that is not necessarily where you're applying pressure while under hard braking. It overlaps a bit but not entirely if that makes sense.