When the grip is done correctly, it is much easier to hit a great golf shot, otherwise many compensations will need to be made during the swing.
This makes it extremely difficult to be consistent. All great players have a great grip.
Many people who have weak/slicers grips have their palms facing each other, which is fine with a putter as this
helps to eliminate the use of the wrists. We do not want this when in the full swing as this eliminates hinging; a vital part of the swing.