True, but putting a bullet in one person is less likely to provoke a certain level of response. Drone bomb attacks are getting a bit too close to full warfare. A big enough drone-bomb is basically a cut-rate, very short-ranged cruise missile.

Easy and I believe already being done in Syria. I'll have to find video links but it's not new at this point.

Drone bombs became one of the favourite attacks by IS militants during the Battle for Mosul. They are a remarkably effective terror weapon, as unlike car bombs, they aren't stopped by walls or barriers. By all accounts they weren't actually particularly effective at actually causing damage.

They were basically dropping 40mm grenades (the kind used in under-barrel launchers like an M203) with fins attached.

Here's a video released by IS showing them purportedly blowing up a humvee with a grenade dropped from a drone: https://www.bbc.com/news/av/world-middle-east-39092883/so-ca...

Here's an article from the BBC with pictures of captured drones: https://www.bbc.com/news/technology-38663394