The last thing you'd want to do if you had to wage war against the US military is use absolutely anything electronic. Even if you were able to hide your holdings of value, you would have to spend the money somewhere, and all of those places would be surveilled. The only way--the only way--to fight against a totalitarian regime in the US or anywhere is to vote--and if you can no longer vote, you're basically screwed.
Of course you should vote as long as you can. But between a full democracy and the extreme totalitarian scenario you're painting, which is basically North Korea, there are lots of intermediate states of autocracy. Even in China, known for their quite developed surveillance system, there are at least 20-30 million estimated to hold Bitcoin and most of them are probably unknown to the government. The "US going authoritarian" scenario would be probably similar.
And if the US military were ever actually threatened by a digital currency, they would simply take it over. For Bitcoin, for instance, this would be a trivial matter of ordering three different public companies to do whatever they wanted.
And what's with the 60% of miners not located in the US? In other countries, there would be even less chances for a government to follow that kind of strategy. Even China seemed to have seen no merit in doing something similar in 2021, instead they opted to drive mining out of the country.
And note that the picture I'm painting here, wherein the US goes into all-out way with Bitcoin, would absolutely mean that Bitcoin plunges in value as all institutional investors, all ETFs, all law-abiding investors, all drop their holdings.
Yes, these 4% of the world population think they are the pinnacle of human civilization and the only country that counts, but they will increasingly be less so
Seriously, this conversation is silly: almost all of Bitcoin's present-day market cap is based on their being a civilization in place that supports a lively financial market for speculative investment instruments. If people want to invest in the end of the world, they should stockpile bullets.
I didn't mention an "end of the world" scenario here, the topic I brought up is "increasing authoritarianism". The demand drivers in this case are not only direct threats to be imprisoned or killed and thus a desperate need to hide your money, but also subjective fears that "something bad could happen" when democratic backsliding threatens to intensify. There are several authoritarian countries where Bitcoin is quite popular.
Of course you personally might not have enough confidence in Bitcoin or any cryptocurrency when authoritarianism threatens to increase in your country, and might like to invest in other things, but many people will. I've seen a lot of posts in this vein all over the forum and in other online communities.