Well, it would be possible if the Argentinians adopted a "South American" Bitcoin variant with their own Genesis block: restarting the BTC valuation process based on their local economy would capture the actual local value.
You'd be in a competition at some point with the larger "Western" Bitcoin variant, but that's not an issue in the short term.
If a "South American Bitcoin variant" was created, purely for south americans, why would anyone holding a world currency (Bitcoin) trade it for currency only recognized in south america?
Maybe I shouldn't have said BTC and that's confusing. Let's say "tamper-proof pips" winkwink.
The global BTC currency is irrelevant to this use-case which is to provide a local people group with a currency option that cannot be manipulated by the same people that screwed up their original currency option but which is calibrated to the economic output of the local people group (e.g. it's not too expensive relative to the per-capita GDP of local Argentinians).
It doesn't matter that BTC exists globally, or at all. The reason I even mentioned or suggested BTC was because (a) it exists, (b) it has certain properties that make it good at avoiding manipulation, (c) that it can be repurposed.
If you replaced Bitcoin's genesis block with a new one, and got a bunch of people to agree that this was for valuation wrt a particular economy (e.g. because Argentinian BTC miners mine on the chain beginning with this block, and few people in the global community do because there isn't an incentive for them to), then what would happen is that the value of that entirely different and distinct economy ought to come to represent the value gained by that group of miners. Who, hopefully, are in Argentina and who trade with other Argentinians. Does that make sense?
Because they wish to do business in South America, or with South American companies.
Economic unity is very attractive, especially considering the financial/legal hurdles that come with reaching customers in a dozen different currencies in a dozen different national jurisdictions.
You'd be in a competition at some point with the larger "Western" Bitcoin variant, but that's not an issue in the short term.