From Wikipedia: "URVs were quoted in cruzeiros reais and its intrinsic value was pegged to three price indices and had a fixed parity of 1-to-1 to the daily U.S. dollar exchange rate."
https://en.wikipedia.org/wiki/Convertibility_plan
The Real Plan in Brazil created a three month period with a combination of the old currency (Cruzeiros Novos) and a new virtual one (URV - Unidade Real de Valor) with an official daily exchange rate between them. This rate was selected to keep the URV at almost exactly 1 U.S. dollar but when both were replaced by a new actual currency (the Real), that was officially allowed to float relative to the dollar.
The real did initially get slightly valued relative to the dollar (an exchange rate of 1 R$ = 0.85 US$, for example) but floated slightly up and down until the end of 1998 when it suddenly jumped to 2 R$ = 1 US$ in order to block a huge wave of speculative money that was destroying economies around the world (having previously hit Russia, then the Asian Tigers).
This still holds for USD
If you're willing to put it in basically "god's hands" (hope America keeps it stable), why not pick something like a commodity money (metals or basket of commodities for instance) that at least somewhat mitigates this conflict of interest. Using _someone else's fiat_ seem like you're keeping all the downsides of fiat but only some of the upsides.
Actually, once the US hits hyperinflation, the US may want to consider using ARS as its national currency
As you lower the interest rate below liquidity preference people will simply hold onto their money because they are speculating on higher interest rates.
The solution seems so simple to me: drop the ARS and use USD as the national currency. Your inflation is just trying to pay for goods and services using an eternally depreciating asset (the Argentinian peso).
The reason this doesn’t happen is because it would mean that the Central Bank of Argentina (CBA) would no longer be able to, at will, monetize the debt of the Argentinian government and favored corporations. Ie. the CBA would lose its ability to purchase a government bond in exchange for crediting the government’s account with the face value of the bond — convert debt into money.
At the end of the day it’s a conflict of interest: the people want a stable medium of exchange and the government wants to finance its activities without balancing its budget.
The economist Melchior Palyi explained this phenomenon in his 1962 book “An Inflation Primer” following the high US inflation of the 1940s: https://cdn.mises.org/An%20Inflation%20Primer_2.pdf