It would certainly make that coin appear to have more credibility in the eyes of some nay-Sayers. Then having a central location to store that gold or any asset becomes a necessity which brings me to the worn argument is that the US will always have the Fort Knox Gold to back up their liabilities (if you believe its still there, "so just trust us we're the govt" ) then counter party risk and trust become the big issue. And trust is a commodity in short supply.