I'm no expert but on the table of example actions and use ratings some actions are "trivial" with NO use rating. For game purposes, a lot of actions are quite trivial, for instance, driving a vehicle. Moving a vehicle around is a lot less difficult than firing and aiming one of its weapons, so for game purposes, attacking has a use rating and moving has none.
However, note that "driving" is STILL an action, and typical minifigs can only execute ONE action per turn. That is why the Pilot skill is introduced, making it much easier to carry on with the game. The person can shoot and move a vehicle at the same time and call it one action.
Now I think you could introduce use ratings on operating a vehicle in some circumstances, say a caveman trying to operate an alien hovercraft. He has no idea what he's doing, so failing a skill roll on just moving the hovercraft might make him uncontrolably crash it into something, shoot off a random weapon, or enter self destruct mode.