A servo doesn't 'rotate' at all, it just turns within a limited range, probably between 60-90 degrees - this can easily be mechanically linked to do steering, and is what they are designed for - all 'proper' radio control models use them.
You're still thinking steppers, where you move so many steps left, or so many steps right (which is RELATIVE positioning, and pretty useless for steering). With a servo you just tell it WHERE to go to (by the width of the pulse), such as 10 degrees left of centre - you don't need to know where it WAS (as you would with a stepper) - you just tell where you want it to go (this is ABSOLUTE positioning).