Literally the only risk mitigation provided specifically by cash is that it can cover you for a handful of days in the event that the electronic infrastructure crashes. So yes, it’s useful to have a bit of cash for emergencies. And I don’t care how much everybody goes cashless — if the infrastructure crashes then all those shops will immediately revert back to taking your cash with pleasure. Unless you’re going to keep literally thousands in cash in your house, though, your personal ability to mitigate this threat by holding cash is limited. And then you have the much bigger risk of being burgled.One thing I just don't understand is how going cashless would prevent you 'saving for a rainy day'?