What is the point of cryptocurrency if your freedom can be impinged upon by being compelled to pay taxes? What's the point of it isn't the primary medium of exchange? If it's not that, then it's just a deflationary store of value, functioning like gold, which nobody uses for daily transactions, therefore of limited value.

Why would that state accommodate your ability to convert crypto into local currency that they ultimately control? The only rationale would be to hurt their presumptive rival: the state you fled.

And more importantly, even if that works at the individual level for you and a few others who work that kind of deal with a state, how does that model scale to populations of multiple 10s of millions?

Another state may allow a few people to make that personal optimization in their territory, but they won't negotiate such agreements with millions of people. If you are a rare wealthy person able to strike such a deal with a state, you are then effectively an oligarch, and part of the state power structure.

States are made of people, and people only trust other people who they believe have skin in the game.