... because mice suck, to be honest. Anyway, I dislike them personally. I very much prefer the controls offered by TWO: you can play an entire TWO round without touching the mouse a single time; everything can be accomplished via the keyboard, and a lot quicker than with the mouse.
Besides, someone mentioned it's very easy to cheat with the "True Swing": you can simply put a ruler (or something similar) next to your mouse, ensuring you will hit the shot perfectly straight every time. Who needs even more cheating than there already is in this game?
Therefore, my counter-suggestion would be: employ keyboard-only, mouse-free mode of playing the WGT game.