Yup, it was basically a dumb-fire nuclear missile - damages both shields and armor, and a single hit was enough to destroy any of the WC2-simulated Kilrathi capital ships.
You could also shoot down your own Mace, which if properly timed, could destroy a whole group of enemy fighters.
WC4 added some limited control to Maces - you could maneuver them a little with your joystick, and you could set them off by holding your missile trigger down until you wanted them to explode.