Personally I think it could hike the price right up for certain coins but that's just my opinon
World Wars in the past have definitely influenced economy a lot because there needs to be a lot of production of all kinds of different items. I'm afraid, however, if we were to go into a 3rd World War, we all know what would happen. The arsenals of the largest countries (USA, Russia, etc.) are enough to essentially wipe out the human race. There would be all kinds of consequences after. If people are to survive, then there would definitely be a downturn of economy after the war. However, during the actual time of the war, production would be high and economies would be doing well. Because of this, I'm almost positive that Bitcoin and cryptos would be in the green.