Apart from the funding and inflation aspect anything that promotes internationalisation may help prevent war. It would be silly for America to have a civil war these days for example, with increasing internationalisation war between countries might also become inconceivable. Bitcoin is an international currency so it may promote internationalisation and reduce war. Maybe
I think you guys have it slightly backwards IMO. You are sort of claiming fiat funds wars which directly causes them. I would claim wars are caused mostly by religion and fiat is pumped out in efforts to get a leg up and produce more weapons/soldiers etc.
So if BTC were to replace everything, they would just pump BTC into the war to fund it.
Most modern wars are fought over, in part some kind of resource that is not fiat based (but the resource can be converted to fiat). Oil and other kinds of energy is a "popular" resource to fight over. In these cases it is not only about the resource, but also the ability to control energy which allows the country to further use it's war machine (as the military uses a lot of energy).