Starting from April 1 2018, every monotributista offering mass-sales* should be able to accept debit and credit payments for any amount over $10 (ten pesos). Non-compliant professionals and stores can be reported and will face a fine from $300 to $30.000 and may be forced to close for some days.
This is the last date to implement this reform which was announced over one year ago, in February 2017. However - the article says - no spike in the usage of ATMs was noted, just a mere +10%. Apparently, the old excuse 'the system is down' is still a favorite, together with a discount of 10% if you pay cash.
As the article in La Nación explain, the seller's net collection will be slight more than 10% less of the purchase price once all costs (for the POS, the transaction, AFIP, etc.) are subtracted.
*professionals such as translators do not need a POS, as they are likely to collect one or less payment per day, anyway.