I could cut your lawn, sell you an Xbox, or buy an old tractor completely with BTC. The government can cry about it all it wants, it can pass a hundred laws, or issue a thousand court orders. But at the end of the day, it has absolutely zero control if two individuals want to voluntarily exchange crypto with each other. We've already seen this play out with the illegal drugs trade and P2P file sharing. Spoiler alert: The government lost.
So really, in FreedomLand, you can work and get paid in BTC, but if FreedomLand only recognizes FreedomDollar as legal tender, then when you need to pay income tax, the government will charge you in FreedomDollar, and you need to exchange your BTC to FreedomDollar.
If you cannot or don't want to pay tax, then of course police will prosecute you, and courts will also require settlements in FreedomDollar. Nevermind you have millions of BTC or XBoxes.
Now of course, this "problem" would disappear if FreedomLand recognizes BTC as legal tender, but now FreedomLand government loses all monetary control, and then economic activity descends into chaos.
Thats a nice theory, but in reality it is false/implausible to be able to control every single on and off ramp in the world.
Evidence: Nobody is currently controlling all the on an off ramps, despite the fact that I have heard the same exact argument that you are making right now, for literally over a decade.