It's not about the game play for you. It's a kind of realism. If you were running a empire or a company you expect people can do some things on their own. Like If you tell your scout to go wild he goes will. He does not need you to tell him where to go next all the time.
I mean real world people don't need a lot of commands like that.
This is useful to play against the computer. You put some units to walk around and find his secret base or hidden units.