There is a large zone between everything is working perfectly and the zombie apocalypse. Power and/or internet goes out semi-regularly (thanks PG&E) and most o

There is a large zone between everything is working perfectly and the zombie apocalypse. Power and/or internet goes out semi-regularly (thanks PG&E) and most of the smaller shops around here go cash-only while offline. Think of natural disasters like hurricanes where power and internet may be out for a few weeks. All those fancy internet-connected payments mechanisms are out and even simple credit card approvals are usually out. Cash is what you need then.