[heavyset_go]

Bombs cause infinitely bigger international uproars for good reasons.

Robot assassins that cannot die change the calculus. Governments don't have to risk losing their human assets in order to take out a target. They can just send out a 4-legged drone to prick them with polonium and call it a day.

[chris_wot]

Which means that governments start making robots that can defend people.

[systemvoltage]

Or nuclear bomb, you know.

[briantakita]

Too messy. Bad press. State actors would also break some sort of treaty without plausible deniability.