If you experience what you call a dead shot, my speculation is it is because you are not winding up correctly and, or, unwinding completely. The ball only goes as far as your backswing windup (top-down), ... and then the amount of "acceleration" and "completeness" of you commitment on the downswing (from ground-up). "Relaxing your wrists" allows the club to hinge at some point during the backswing. That means you'll have to un-hinge somewhere during the downswing*. That un-hinge for about 80% of golfers, turns in to a "flip" (ball goes a bit farther, but not on line or goes left-right hander)... and for the other 20% that don't un-hinge, a nice "slice" or "shank".
This method (once learned), allows you to keep the ball straight (I think maybe 70% of the battle in the game). Then if you learn to coil/uncoil correctly, you can hit straight and as long as your body make up can produce (everyone is different and at different stages). Hitting the ball straight, beats out long every day of the week. Moral: You can hinge or relax your wrists and if it works for you do it! I know the majority of golfers that have active hands during the swing struggle. That is why I developed a more reliable method that uses large muscles and can produce very Long & Straight shots regularly, not by luck occasionally. *If the hands/arms actively do something during the backswing, the body stops rotating ... the shoulders stop turning, and you get a weak lifted hinge. This prevents a correct windup using large muscles.
Move Less ... Get Good! DUPLESSISGOLF