You may, if I understand your drift correctly, have a fundamental error. But then I may not understand it, and we may be in agreement.
Yes, I think we are actually in agreement - your final line suggests that we are.
If people are using both national currencies and crypto currencies, what is the effect on government and private actions? In particular, is there an effect on the likelihood of war?
I had, for the sake of speculation, assumed away all competing/existing national currencies. But, I am very interested in the tradeoff you are asking about. It seems possible that both national currencies and cryptocurrencies can both be used to finance war and their dual existence might actually make it more possible for tge creative financing that could mobilize military resources.