A government will "let an anonymous currency get traction in their country" in order to forestall a revolution and ensuing regime change.
In Wences Casares' scenario, the first country to defect from the petro-dollar world order and adopt crypto is one that has *ALREADY* been damaged beyond repair by fiat and central banking.
By taking a chance on crypto e-cash, a devastated basket-case economy like Bolivia, Haiti, Ukraine, Venezuela, or Argentina has nothing to lose and everything to gain.
Once a national currency offers/approximates the safe harbor guarantees of Bitcoin/Monero, others will fall in line like dominoes as Gresham's Law penalizes late movers and lavishly rewards first defectors.
A country won't make bitcoin the official currency if they have no control over the cryptocurrency. At best, they'll just say "people can use whatever currency they want" and the USD or EUR will become the de facto currency.
How do you know that? Crystal ball or psychic hotline to Ms Cleo?
You don't know what a country will or will not do, especially when in the throes of mass social unrest following economic collapse.
.gov JBTs can always tax real estate and other illiquid fixed assets. They'd rather give up some control (and keep their cushy phony-baloney jobs) than lose all control (and be swiftly hung from the nearest lamppost).
The point of making cryto official is that the politicians and central bankers of that country are *RENOUNCING* their prerogative to interfere with the free market. That's what would trigger a surge of capital inflow, and encourage other impoverished jurisdictions to emulate their example sooner rather than later.
You think Satoshi didn't think through and plan for the beginning of the fiat endgame before he published the Genesis Block?
All these incentive structures were war-gamed decades ago, long before Nakamoto Consensus solved/worked around the BGP and turned theory into practice.
Bitcoin and Monero were created to shape the battlespace in our favor....