Gold and silver coins can be easily converted to cash in just about any city.
That’s useful for all sorts of things that might cause you to temporarily or permanently evacuate your home town/city. Tornado, hurricane, earthquake, contaminated water system, weather related power outages, forest fires, chemical spills from a train derailment, etc, etc.
A stack of $100 bills is also useful. Maximize your options and you’ll be in a better position to handle the unexpected.