That only impresses birds and monkeys. Well-aimed, controlled, single shots or three round bursts do the job nicely without drawing undue attention to your position. Grenades and explosives are even better. Tear gas and white phosphorus is better still. Because of the environment, command and control quickly breaks down while troops are under fire.
Communication becomes impossible.
The troops can not see or hear in most cases. For these reasons, small, well-rehearsed groups had an advantage over large ones. Professional race car drivers know that you can sometimes gain control of a vehicle in a crash situation if you keep your head and remain calm. If you lose your cool, it is impossible.