The vast majority of US hundred dollar bills are not in the USA, nor is their value particularly linked to US inflation. A Big Head hundred is worth what its worth, today, here, or in Russia, or in a dozen other countries where it remains a much more trusted currency than the local ones.
The cost of gasoline in Texas doesnt really impact the fact that US cash is still safer than a Banco Nacion account, or a Mercedes sedan, in Argentina.
Plus, anyone who has actually lived in the USA for the last ten years or so knows that the official inflation rate is selective and decieving. Rents and house prices have gone up far more than 7% a year for years. Food has increased in price, both to buy at a market, and to eat in a restaurant.
Inflation only has meaning in terms of the cost of living versus wage ratio- and wages in the US have been stagnant for 40 years for a good 2/3 of the population.
Anyway, Argentines will continue to use dollars, because they are liquid, small in size, and hold their value pretty well, in the bigger scheme of things.