Many (including me personally) obviously misunderstood some things that were communicated through this forum - because Milei was mentioned on the forum primarily in the context of Bitcoin, in other words as someone who supports it and who will popularize it in some way (legalize) in Argentina.
"General forum opinion" is correct in that Milei probably is not a friend of too harsh Bitcoin/crypto regulation. Contract law was also already flexibilized, allowing financial contracts in units different to the Argentine Peso, including Bitcoin.
Bitcoin-related regulations were however never too strict in Argentina, with the exception of the ban for banks I mentioned, but that measure can be understood in the context of a year of financial instability (>150% inflation in 2023).
But I don't expect Milei advancing in the direction of Bitcoin as a "legal tender" like in El Salvador. Simply because he probably doesn't support the concept of a legal tender at all, due to his ideology that all currencies should compete freely.
Regarding reserves and mining, it's interesting that an argentine state company, the oil corporation YPF, already mines Bitcoins since 2022. It has recently announced to expand its mining activities. However, I have never seen announcements regarding holding these coins.
If his opinion is that currencies should compete on the market, then Bitcoin does not have much of a chance considering that most people use it as an investment, not as a currency.
Yes, it is likely that mainly the US dollar benefits from the "free currency competition" if it is finally introduced by the Milei government. Argentina is heavily dollarized since the 90s at least, most people use the USD to save money. The USDT and other dollar stablecoins have recently got some attention because their acquisition is much easier than of the USD. But Bitcoin is indeed more used for speculation, like elsewhere. However, there are businesses that accept Bitcoin and cryptos, above all in the tourism industry and in IT-related services.
As in Argentina cryptos were mainly considered a means to circunvent the restrictions to acquire foreign currencies like the USD, it is unclear if the lifting of these restrictions (planned for 2025) will benefit Bitcoin or not. About 15-20% of Argentines hold or have held cryptocurrencies according to estimations by several sources (Triple-A, for example). However this includes the USDT, and USDT holdings will probably dramatically decrease once the restrictions are lifted.
My prediction is that Bitcoin will benefit from the general more libertarian/liberal financial policy of the Milei government and also from the current attention it generates due to the bull market, but the percentage of people holding cryptos could lower to 10-15%. However, I think stablecoin-holding people aren't that important for Bitcoin adoption so this may not be actually a negative development.