All this cashless society has the main problem that during any serious cataclysm that kills the communication infrastructure the trade just stops. Not only the global nuclear cataclysm and EMP but any kind of local cataclysm like Katrina or war in Syria. And if the trade stops the hungry people could rob since they could not buy.
Moreover, I feel that the more Western is the society the higher the unrest. Some Somalians could organize a government-less society based on traditional law, in the First World it's just impossible. We Russians survived the wild capitalism of 1990-s because in any crisis there was impossible to foreclose or cut off the electricity and heat. Next such crisis could produce hordes of homeless.