ATHENS — In the central market here recently, hanging above the trays of cod and the slabs of pink meat, was evidence that Greece’s near bankruptcy last summer was having an unexpected impact — shiny new placards advertising that, at least in some stalls, customers could now pay with debit and credit cards.

“If I like it or not, people are asking for it,” said Christos Papoutsis, 57, a butcher here who finally yielded to plastic money only last month. “If I don’t accept the cards, I will lose sales.”

Economists do not generally see much to celebrate in the shuttered banks that followed Greece’s cliff-edge negotiations with its creditors or in the capital controls that are still in place, limiting Greeks to cash withdrawals of 420 euros, or about $457, a week.

Yet experts say that these events have created an unforeseen silver lining for this troubled country. They are spurring a great leap forward in the use of electronic transactions, which could make it much harder for corruption to flourish. Many say the government should act quickly with added incentives — like tax breaks linked to the use of the cards — to take advantage of the moment.