Probably an exaggeration, but caveats apply.

Say, you get paid in USD.

    You got paid: 10000 USD

    Income tax: 15%

    Government exchange rate: 130 ARS per 1 USD
    Unofficial exchange rate: 330 ARS per 1 USD

Now, if you do things like daddy government says and use the official rate, you end up with this amount:

    10000 USD * 130 = 1300000 ARS  and then  1300000 * (1 - 0.15) = 1105000

But if you do what's good for you and still pay taxes to not go to jail:

    10000 USD * 330 = 3300000 ARS  and then  3300000 * (1 - 0.15) = 2805000

Now consider your "effective" tax rate:

    You got paid: 3300000 ARS (fair market value)

    Government rate: (3300000 - 1105000) / 3300000 = 0.66
    Unofficial rate: (3300000 - 2805000) / 3300000 = 0.15

Note that it's before you consider future devaluation of peso. For tax purposes you can say you received 3.3M ARS, but just keep it as 10k USD. Then your effective "government cut" rate over the years could very well be in 90% territory if you do the stupid thing and hold pesos.