In Halo 1, you are required to empty an entire clip into the enemy in order for them to explode from the missles. In this game, you only need to empty about 1/3 to 1/4 of a clip for the needles to blow your enemy up. This is even more effective when you dual-wield them. Also, on the first couple of missions at least that you have to do as the Arbiter, most of the enemy grunts carry needlers, making this weapon even easier to use.