My contention, and I'll admit it's wholly academic
And I would have been happy to stay home in 1991. I'm sure Dad would also have been happy to have stayed home in 1967-68. The fact of the matter is that warfare is endemic and no matter what we'd prefer, we often have to make that sacrifice.
However, we can't call ourselves a morally-superior system when we engage in the deliberate infliction of suffering on the innocent when we do it (and call it virtue or mercy), and then call it somethign else when an enemy does it.
I have no doubt that had Germany or Japan possessed such weapons they would not have hesitated to use them, but it does not automatically follow that they would have affected the eventual outcome, particularly with regards to Japan. And the fact that I can't prove otherwise (and neither can you -- history doesn't work on "What if?") doesn't make the concept invalid.