For those that haven't been to Argentina, you have to realize, there are two rates. The "official" rate and the Blue dollar rate. The Blue rate is the real rate. That's what everyone uses when you're buying anything in Argentina.

The official rate is only used for credit cards when foreigners are stupid enough to use them. It's a way for the government and banks to rent-seek. 

The devaluation is just bringing the official rate to be the same as the Blue Dollar rate, nothing more. It's not some grand conspiracy. It's just recognizing reality.