The gun is pointed at the target (or at least very close to the target) for a longer period of time. Your eyes have more time to force the sights to line up. Not as much time as people originally teaching the press out taught (IME), but still more time than a true index "escalator" type draw. Your finger has more time to remove much of the trigger weight and travel distance, which usually leads to better, more consistent accuracy.
Obviously this isn't true for everyone, for a variety of reasons. For the professional user, this still represents the fastest way to get better, with less practice, that I know of.
eta: As I've said before, the press out really shines with DA guns. A 1911 with a sub 2# trigger doesn't need much in the way of technique, to get a hit. A duty weapon will usually benefit from the press out.