It does have a lot of impact on the quality of your shots. Making a slice or hook is often caused by poor grip strength.  When you ask a lot of experienced players, the first thing that they adjust when they notice some variances in their swing is their grip strength and stance. If either one of those is not right, you will definitely see issues with your swing, and the tendency to make slices and hooks will be greater.  You have to fix your setup to resolve your swing errors.