But I still find it hard to believe that would bring the Panamanian or Salvadorian jeweler any benefit, let alone the rest of the population. The problem of converting the BTC rests with them after the purchase.
There are already some countries that made a business of looking the other way when somebody wants to launder some money, that's been going on forever and isn't related to Bitcoin. The benefit to the population is that because the government gets to tax some part of the activity, the people's taxes are lower and the government can provide better services than it would otherwise. If this makes a country a kind of a tax haven, but for Bitcoin, then that's probably just business as usual, in a way (still wrong, though).
Enabling ransomware criminals, you mean.
But I still find it hard to believe that would bring the Panamanian or Salvadorian jeweler any benefit, let alone the rest of the population. The problem of converting the BTC rests with them after the purchase.