Did it matter to frontier stores that the American dollar was backed by gold? Was there a backstop holding the financial system together?

People often say that the gold standard is unworkable because there is not enough gold in circulation to back up the value of all the cash assets now stored in banks. Did it matter to frontier stores that the American dollar was backed by gold? Was there a backstop holding the financial system together? Considering that local stores and home-grown banks can organically develop and create their own forms of credit, what good is a national currency, or attempts to connect financial markets beyond the immediate area?