The single most important moment in the golf swing is impact, and if your positions are bad when you arrive at impact you’re in trouble.
For many average and higher-handicap golfers, their impact issues are caused by flipping their hands at impact instead of maintaining lag and forward shaft lean.
Ideally, you want to hit the ball with, not just your hands, but with your bigger muscles. What some call a full body swing-where the core muscles rotate and control the arms through impact- recruits bigger muscles to produce the swing. You create more power with faster clubhead speed and less effort.