Is war good for everything?

No it's bad for anything, take Vietnam for example I was there in 1966-67 battling to remain alive, a great deal of us didn't, and what was the purpose, all things considered, individuals presently go there on their days off, same in Japan and Germany....

Even the winning side loses a lot. 

No. If you nuke them into dust then you can’t play war anymore. 

Not when our soldiers die in them. 

No, not everything. 

By the way, I have been through 2 different wars, 3 different times. It sucks, especially,  for the people that have to go through it. However, war has its purpose. 

I only fought in one war in my life, and I can say for sure that it was not good for anything. I have found that it is usually people who have never fought in battle that have the idea that war is somehow a good thing.