At least with Visa Intl. (not only US cards - there are also other countries in the world ) issued outside Argentina it is openly advertised https://www.visa.com.ar/support/cons...-english.html# that the conversion rate will be the favorable MEP rate https://www.cronista.com/MercadosOnline/monedas.html which is slightly less advantageous than the "blue" rate.

Visa has also a convenient conversion tool which lets you add the foreign transaction fee applied by your bank https://www.visa.co.uk/support/consu...alculator.html (for example ARS to CHF with 2 % bank fee would make CHF 210 for ARS 100 000)

I did not find such clear statements from Master Card or Amex and would stick with Visa for Argentina to avoid the stress of the "cuevas" and / or the "arbolitos".