The IMF are just trying to protect their paymasters and keep their ability to interfere in other countries' economic policies.
As for which other countries will make crypto a legal tender; I reckon look for small countries that are not friends with the United States but are also not too closely aligned with any particular other power bloc. Places like the Seychelles and Maldives are a good possibility.
It is also worth looking at countries which might not make an actual policy decision, but where the citizens make it a fair accompli, either because the economy is in trouble, because the government is relatively weak or distracted, or because the banking system has done something to show ordinary citizens it is not to be trusted. Canada, Ukraine and Russia are already some way down that path, and places like Haiti, Somalia and Ethiopia are good possibilities.