Maesfen
Extremely Old Nag!
It puts additional pressure on the horse via the nose, and they really do seem to behave better, and have more respect for you. BUT it should only be done by someone who knows what they're doing (not saying you don't, just for other readers).
You may find a dually headcollar, or a controller headcollar helps. I have a thin knotted headcollar as my lad can be bolshy, and it works a treat.
A rope around the nose, even in the hands of a novice (which OP plainly isn't
If it gives you that bit of respect you need OP then there's nothing wrong in using it to your advantage at all but don't fall into the trap of using it all the time otherwise it won't always have the same effect.