On the show Cops I saw a policeman come up to the front windshield of a car and pointed his handgun straight down at the suspect, he had to hold the gun high requiring him to hold it sideways.
I can also see if somebody was shooting somebody up close, holding the gun high, pointed down on somebody kind of makes sense in a crowded room. Shooting somebody from up high the bullet will shoot down instead of across the room. Does that make sense?
Just picture it. Grab your Glock and try it. LOL