The point of the arms only tee drill is to work on bat path as well as keeping your hands inside the baseball. When doing this drill, the hitter should only be hitting baseballs to the opposite field.
Staying “inside the baseball” forces the hitter to see the ball all the way in, and not jump out in front. It causes the hitters hands to be in a stronger position on contact. Working on hitting the ball to the opposite field in practice reinforces this habit.
