Not all businesses charge your account in real time so cards will work in many locations regardless of connection to a financial institute.

The gas pumps at my corner store only charge your account one day of the week. I can have a zero balance in a bank account, buy a tank of gas and they don't ping the account for money until Friday.

A Richmond, VA toll road had one booth with a problem--it held all credit bank card transactions for six weeks until it was rebooted a few years ago.

People actually were stupid enough to try to blame the highway department for their overdrawn accounts.

If I charge $200 on my bank card this month and it hasn't come out of my account next month I have sense enough to know it will come out eventually at any time when least expected.