I believe weaponized drone swarms should be categorized with chemical weapons, cluster munitions, etc. A few thousand drones carrying shrapnel explosives and trained to recognize humans is basically a mobile minefield. It’s terrifying, really. I expect they will be used heavily if WW3 comes around, with devastating effect. Much like horse mounted cavalry encountering machine guns for the first time at the beginning of WW1. I’m not a weapons expert, so I could be wrong, but it seems so cheap and practical I can’t think of a scenario where it doesn’t happen eventually.