As Vis mentioned, it is the better option if the government can't stop itself from printing money and fucks everyone over.
This is the inflation rate of Ecuador before and after they adopted the dollar in 2000.
Milei now wants to do the same. At least this way people will be able to save (and spend their savings), and the government will have to be fiscally responsible.
The world has run directly or indirectly on gold (which can't be printed) until 1973, so it's definitely possible for an economy to work with a currency you can't print.
Comparing Milei to Trump or Bolsonaro is very, very misleading.
Milei is has radical capitalist / free market ideology, but is far removed from social conservatism.
Just to give you an idea, he wants to close the argentinian central bank and kill the national currency or let it kill itself with a free floating exchange rate.
Such a move is the opposite of what alt-right / fascism would do which seeks governmental control of media, industrial and financial institutions.
If anything, the current ruling party "Union for the motherland" (Union por la patria) openly advocates and defends Peronism which is a sort of decaf fascist ideology heavy in nationalism and populism thinly clothed in laborist rethoric to make it seem left wing. Current ruling party which btw has lead the country to over 300% inflation (if you take the free exchange rate as a reference since the official exchange rate is manipulated and it is illegal for argentines to freely buy foreign currency except for a small token amount).
Just to make it easier to understand. If you're familiar with the political compass:
These are three very very different quadrants.