Assuming your counter-attack doesn't make the difference between complex civilisation surviving and being wiped out on Earth, it has the potential benefit of pr

Assuming your counter-attack doesn't make the difference between complex civilisation surviving and being wiped out on Earth, it has the potential benefit of preventing the initiating party from repeating their attack against other nations. Even if the initial launch was a genuine mistake, there is some value in launching a retaliation because it prevents such mistakes (or "deliberate mistakes") from happening in the future. In fact, seeing how much the mistake costs the initiating party may be sufficient motivation for all the remaining countries to properly commit towards disarmament.