Well that is more about simple and consistent setting of the rear wheel in the dropouts... Being able to properly align the rear wheel will give you a more positive grip when tightening your rear skewer... If your rear wheel is askew (even a little) than you really only have the friction holding your wheel in place at two points on both sides of the skewer, whereas when it is properly aligned wheel will have the entire circumference of the skewers nuts and hub making positive contact with the dropouts.

Who knows though, maybe I'm just not manly enough to pull my hub loose lol.. (FYI I’m a 235lbs guy keeping up with A rides on my steel commuter..)