You think that if these weapons weren't used the cold war wouldn't have been so... uneventful? It's a fairly logical conclusion that the cold war wouldn't have been so cold if these weapons weren't used in Japan, not bottom talking.
Actually, had the war ended without any nuclear bombs being dropped, the awesome power wouldn't have been seen, no one would have known the USA had them, in all likelyhood it was largely the very event of the bomb going off that led most of the other superpowers into their programs to create them in the first place. Frankly without that bomb going off, Russia wouldn't have been as powerful as they were during the cold war in terms of, they wouldn't have been so advanced in their nuclear weaps program and frankly the collapse was coming anyway there so realistically the cold war would most likely have never happened.
A chain of events, it was the bomb being used and announced publically that sped up the investment and manpower in the Russian program.
As for if it stopped the war, many many people including military leaders of the time think/know Japan were days/weeks from surrendering so it didn't stop anything.
It was a terrible act but if you have to look at things on a scale there were more people tortured to death in total in concentration camps. Most of those that died in the bomb didn't know what happened, most of those in concentration camps spent months dieing in pain before being burned alive but much more slowly. In terms of numbers, pain, torture, suffering, its no where near other things.
How about people swapping kids with their neighbours so if people come through their village they won't be forced to rape their own kids, but their neighbours. THen being cut up by machete's, the bomb despite the large number in one very short space of time doesn't rank close to the biggest attrocities on the planet.
As for the targets they go for, Total war, what BS. Its an excuse to make people feel better, everyone in the UK was supporting the war effort yet we are disgusted by the idea of enemys targetting civilian targets, think of terrorism which is mostly aimed at civilians and how we react to that. We should have really targetted anything but a large city, the scale of destruction was apparent, if it was down over farmland killing a handful the same message would be sent.