>>63929482
The failed to adapt their aircraft to keep up with the Americans, and failed to train pilots to replace losses, so turning vulnerable planes into guided bombs did increase hit rates. Along with creating a psychological effect (One which contributed to them getting nuked, but that's another issue.)
If the invasion of Japan actually went off, Kamikazes would have played a big role. Thousands of aircraft, frogmen, boats and subs in hidden positions. Most probably would have been killed before causing damage, but the USN and RN definitely would have taken more casualties. Enough to force an armistice? Highly doubtful.