But his financial acumen is terrible - one bankruptcy after another. I don't see how that would lead you to think the costs of war would discourage him.
Hillary might well go to war too - it would be far too optimistic to deny that. But Trump will. Not might, will. He likes violence, hates brown people and makes rash decisions all the time; that is the perfect recipe for a warmonger.
As for being too stupid to be dangerous - that didn't work so well with Bush.
Trump stands on stage impersonating a disabled reporter and you still prefer him.
He can get away with any fucking thing he likes, it seems. Can't see that being a deterrent to war either.