If a currency like Monero with further developed scaling and privacy features is able to gain a foothold in developing nations, and enough off-ramps are set up via decentralized exchanges like Bisq and through direct acceptance for goods and services, then it is difficult to see the spread stopping between nations with reasonably free Internet, especially as factions within each government will likely have some direct interest.
The US dollar will be least threatened, the longest.
However for decentralized people to people transactions, monero may have its chance.
Since I’m far from a crypto bro, I wasn’t suggesting this ;)
I don’t even own any crypto.
As cryptocurrency already requires the safeguarding of a private key or a custodial partner doing so, and generally do not accept rollbacks on the base level, there isn’t that much added drawback to making strong privacy default.