I had saw a video complaining about the current system of fiat, that its printed to cover and to pay for wars, hidden the big problem around fiat, thats bad management, and no transparency. Bitcoin would be amazing to any country has we will see where the money is being invested, something we dont know is the numbers and costs of each transaction.
Bitcoin can also pay for war. That will just be the same as fiat. It will always depend on its user on how he will use it. If the government wants to cover up the war expenses through bitcoin they can do that also.