The reason for this goes back to situations in where leaders, Non-Commisioned officers and officers would have to make swift decisions in the battlefield that may affect the lives of their soldiers. In a world of chaos, their subordinates are relying on their leaders to make the right decision and trusting that those big decisions made is the best out of all the options given.
Marine Corps. Marine Corps pay grades for officers have ranks similar to the Army and Air Force. Company Grade Officers (O-1 through O-4): O-2 is generally automatic after two years as an O-1. O.