I suspect that a backed currency could not be as rapidly or radically manipulated as an unbacked currency.
Granted, gold or silver does not pay dividends or seem like a good a good investment right now, but if our faith in the almighty dollar ever vaporizes completely like the Weimar mark, a few gold or silver coins might get you out of a "tight situation" quicker than a pile of worthless paper.
So it's a hedge. That makes sense. But you don't use it to pay your mortgage nor buy your groceries nor pay for gas in the real world absent that "tight situation," because with gold, you always have to haggle, unless it's a gold coin, and even then there's always sweating, clipping, and for large payments, hiring a guard.
And when you start talking about gold backed paper money, then you aren't any better off in that "tight situation," are you?