 Why is Rolf's weapon so valuable in the fights with the Furry?
Rolf swung the lax controls over hard as the bursts of fire revealed a looming barrier of stone dead ahead, and then he felt the tough skin of the flyer crumple inward. Toward this barrier the spinner bore him, and Rolf was content to let it move in that direction—from the heights of the wall he could scout out the country beyond. Deftly Rolf nested the spinners again in their pack before he set out toward the heaped-up mass of stone blocks that was the wall. A hundred paces away Rolf made the dark shapes of armed warriors as they filed downward from the Barrier into the blackened desolation of the desert half of Lomihi.
 It's much more technologically advanced than theirs.
 The Hairy people need all the extra weaponry against the Furry.  He's able to catch the Furry off guard with his expoder.  It's much more technologically advanced than theirs.  He's a skilled marksman and able to hit many targets at once.