People do it because it minimizes their profile, making alot less of you to hit and the only part that sticks out should be a covered tank and a padded jersey, allowing only areas that have a better chance of bounces to show.
What you mean to say: "People tuck themselves in because it reduces the size of the target to hit, while at the same time, providing the only parts showing should make bounces much more probable if done correctly."
It hides a large part of your gun, if you dont think it helps, then feel welcome to stick your hopper out first in speedball.
If you tilt your loader behind the bunker, you're exposing more of your mask in its place. Anyone have the links to the old Joy Division snap shooting tutorial? It outlines the concept quite well.
Well would you rather have a mask that has a chance of a bounce? Or a hopper that will have none at all? The bottom of flexible masks were specifically designed to increase bounce probability, no hopper has any bounce chance.
You arent exposing the bottom of your mask...you're exposing more lens.
Plus,coming out without tilting gives you a long, skinny profile which is harder to hit than the short, wide profile tilting gives you.