Somebody said it earlier, closer to what I think is going on.
AFIP wants to catch people spending dollars/foreign currency they shouldn't have.
Many Argentinos I know have bank accounts out of the country, many in the US, that are full of dollars. This is a way for AFIP to track people who buy trips/vacations, etc, here with their foreign credit cards or cash, possibly from money that was made in the black and deposited (either directly or by carrying) in another country.
I'm sure people who can't explain their foreign funds will become under scrutiny by AFIP.
I don't see how it would stop Argentinos from taking cash out of ATMs from their foreign accounts and paying in pesos. The article seemed to be talking about reporting transactions (purchasing tickets/packages) requiring currency conversions.
It also doesn't restrict travel, except on the doubt of the travelers themselves. If they do everything in white, they would have no problems. In reality, it could be seen to restrict travel for the very reason that many people do not exist completely in the white here, but I don't think the point of the law is to restrict travel itself.