Part of being a great ball striker is being able to predict the outcome of a shot before it is hit and predicting the curve on the golf ball is a huge part of that. Where you put the ball in your stance has a huge effect on predicting the curve of the golf ball.
If the ball is back in your stance, you’ll swing more in-to-out — producing a draw — and if the ball is up in your stance, you be swinging more out-to-in — producing a fade.