I have definitely seen the drill were they stop at contact. Her coach is actually insisting that they stop at contact during the game.
helps Define bat angle approach to the ball and where bat and body is at contact.we do a drill where she stops at extension. We will do this when she is cutting the ball.
I’ll add that it would take a massive amount of hand strength to actually stop at contact. Have seen some drills using a lite bat or pvc pipe with wiggle balls to stop at contact. Might want to ask the coach what the purpose of doing it is.