The Greek payment system was not the problem, in the summer of 2015… Banks were.
Greek tax payers have to foot a 25 billion bill (excluding interest!) for another rescue of their banks. What happened? The ECB did not prevent – nay, even triggered! – an bank run. A very limited bank run, in fact, as the amount of money on sight and overnight deposits (the accounts one uses to pay her or his bills) barely changed. The payment system was not in jeopardy. The banks were, of course. But let those banks go bust (and finance all deposit claims with money printing, cash, by the ECB, to prevent money destruction). The truth is however: trust your mattress – not the ECB. I mean – aren’t Eurozone citizens allowed to use the magic of the market and move their deposits to another bank, or another place once they do not trust a bank anymore? No, they aren’t. We are allowed to change to another supermarket. Not to change to another bank.