Consider a punter who can put the ball on the one yard line, inbounds or out of bounds, instead of a touch-back
where the ball comes back out to the 25 yard line. His leg is so powerful that, on long punts, the special teams guys likely won't be able to get downfield fast enough to pin the ball down. Therefore a punter who can create that kind of placement/positioning of the ball would be an incredible weapon.
Think of what the AZ punter did. He kept the ball down near the one yard line which created the safety that turned momentum around.