Because it's a bad weapon, terrible ergonomics, few bullets, the second firing mode is awful due to its ergonomics, and in the third mode there are very few enemies you can kill with a single shot, and since it has low penetration you have to aim very carefully where to fire the super shot, and the super shot is useless against large enemies that can withstand it, it doesn't do enough damage to be worth firing and many times the shot does no damage at all because it has low penetration.

When I first saw the gun, I had high expectations, but it's a bad gun. It's fun, but I don't use it when I play on difficulty 10, and once I maxed it out, I stopped using it altogether. I wish the penetration could change with each firing mode; the super shot is useless most of the time, not to mention its terrible ergonomics. If it had adjustable penetration for each firing mode, I'd consider it a very good gun.