Everything runs on liquidity. Unless you know something I don’t, that dollar bill in your pocket is just as likely to buy a can of Pabst Blue Ribbon today as it was yesterday, and will be tomorrow.
Or you could sell 1,000 lbs. of gold – if you have that lying around – without fear of completely scuttling the global gold market. Your bank has to have cash, liquidity, lying around somewhere in the back if it wants to stay in business.
And in many cases, it’s easy to see or verify this liquidity. It helps everyone feel better about doing anything.