Anecdote but I was there a few weeks ago and did have a similar experience. It was really annoying, so many small shops chose not to take card, and as tourists you usually get screwed on the exchange rates if you need cash. Also a concert with 20k people attending, none of the card machines worked, and no one seemed to kick up a fuss just paid cash, while we had none with us so had to "enjoy" it without drinks or food.