Gold has a reasonable place as part of a diversified portfolio, but it is more of a conservative store of value and a hedge against inflation and US DOLLAR weakness (all commodities – for instance oil- tend to move in the opposite direction to dollar moves.)

It should be noted that:
1) an investor carefully picks the currencies he has his assets in – for some time now, US Dollars have been eschewed in favor of the Yuan and the Euro and the Singapore Dollar and the Yen and the Swiss Franc, for instance. No need to focus just on the US Dollar. I converted 90% of my dollars to Eurpos and Yen last year.
2) You don’t just put your wealth in a currency itself, you choose an investment vehicle that EARNS A RETURN.
Gold’s 5% AVERAGE (there have been many LOSS years) over a LONG period of time is easily beaten by any number of bonds and cash-dividend-paying stocks. For instance, I have some money in 7.75% (AFTER TAX, so no deduction for tax) RCBC Bonds, and in blue-chip high cash dividend stocks like Globe telecom (about 11% cash dividend yield) and BPI (about 7% cash dividend yield.)
Since I am in my sixtees, I tend to be conservative, and the RCBC and other bonds earn EVERY YEAR, plus the Peso appreciates against the dollar so there is that gain too, against the dollar. Gold earns no interest, only appreciation AND depreciation, in price.

As Randell says in his blog, “It depends on your financial objective, time frame and risk tolerance.” Gold is a reasonable PART of a balanced, diversified portfolio, but it cannot at all be said as a blanket statement that gold is superior to currencies.