Yeah but that doesn’t happen. Cash payment is the default standard that backs up the other forms of payment that depend on Internet / phone infrastructure and electricity.
No business that I have ever patronized has refused cash, but many have been cash only and were not able to accept cards or contactless payment. Power outages, Internet outages, etc all can bring down payment systems’ infrastructure.
That’s how it is in the USA, and it’s a good system. Cash is reliable and puts the entire monetary purchasing power into the literal hand of the citizens, versus cards and other digital payment systems that can be controlled by authorities to deny your access to your own money.