Yep, it's too make sure we have few enough that they can all be preemptively disabled.
Exactly. It’s like arguing that army arsenals contain 1000 times as many bullets as needed kill most of an enemy. That isn’t the point. The arsenal has to be big enough so that you don’t run out of ammo at the point where the bullets are being used, the exigencies of supply and combat being accounted for. Ten 1ookT class weapons going off anywhere in the world would be a really bad day for all of us. The way to stop that is to make sure that the perp is going to have his last day on earth.