>but it did not cause the kind of damage that is claimed for this weapon

I don't know, what you are referring to here, but to my opinion, given the distances of a relatively wide area with very limited population, the results where grave enough. Generations of the inhabitants where contaminated and had babies with many defects or deaths born. I guess the descendants of these poor people still struggle with the effects of this bomb.

Given such an event in or near a city of the US, I guess not only one city might get wiped out but the effects would be very real and destructive in a very big part of the US.