In bowhunting, you must prepare for the unexpected. Let’s say you range that bull elk at 40 yards, and set your sight accordingly. You come to full draw, and he suddenly takes a few hops away. With multiple pins, you at least have other aiming references available if there’s not time to let down, range again, and move the sight. Also, more pins mean more distance. Any pins you have under the top one extend your range, enabling you to shoot farther with a dedicated aiming reference.