Aren't Paraguay, Brazil and Argentina in the same trade union? I don't know the details of Mercosur but in the EU you can buy whatever you want in any other EU

Aren't Paraguay, Brazil and Argentina in the same trade union? I don't know the details of Mercosur but in the EU you can buy whatever you want in any other EU country and take it back home without the need for customs. Where is the black market part of that trade? As for your trade example I would like to see the details of that. There are not a lot of vendors that accept crypto and those who do, use 3rd parties which then usually require some amount of KYC (even if it's is minimal). Combine that with how many vendors are actually able/willing to ship to the country in question and you are left with a very small set of online stores. Add shipping costs and custom fees that will eat in your margin. So yes in theory you can setup an import/export company empire in order to exchange your crypto into local currency but that is pretty much the definition of "not scaling". My point is: if a country wants to make cryptocurrency useless they can totally do it.