[ssully]

I think it's just a way people can relate to a disaster. It's incredibly difficult to comprehend the damage of an event like this. Reducing it down to the number of lives lost, or money in damage adds context that people can understand. Though I will say even that is imperfect, because understanding what 1000+ lives lost actually means is pretty difficult.

Either way it's an imperfect solution, but one that can get a quick point across to people that this is a horrible situation.