Literally all forms of money ever invented are based on faith. Even the importance of debt (which existed before money) is based on faith.
You can't eat gold, you can't grow food with the wasted energy underlying Bitcoin. You need faith that in the long term people will give you something you want in exchange for your monetary tokens, and that the prices of goods will not grow or shrink too quickly so as to make those transactions untenable.
Sovereign nations have several levers to ensure their national currency continues to fulfil these requirements so as to encourage faith in their currency. Magic internet money does not.
How poignant of an image: you're holding your dollars, "the military" is standing in front of you...and the rest of the world is just walking in the other direction.