What are the "pros" and "cons" of using a hackamore?

A hackamore is like a halter in that it puts more direct pressure on the horse’s face (nose, side of the face, or chin) and creates a direct response. For example, when you pull straight back, the pressure is on the nose, and the horse should step back away from it. Pulling on one rein to the side creates pressures on the side of the face that the horse can move away from. So the pressure of a hackamore is …