In difficult times, it is easy to blame central banks for everything. Part of their role, after all, is to play the scape goat for policies the politician do not dare implementing. But then, there is only so much the central banks can do, as Europe and the United States no "nicely" show now. A substantial ingredient in the blame game is a call for a return to the gold standard, a nostalgia for supposedly better and easier times.
Olivier Ledoit and Sébastien Lotz echo this call and study what our current understanding is about the coexistence of fiat and commodity money. In principle, we can start from the idea that currency competition is good: this would force the central bank to be more careful with its fiat money. Indeed, we have learned from money search theory that bad money does not necessarily chase good money (the old Gresham's Law). Also, if the commodity has a positive return, its monetization is beneficial as long as its storage and transaction cost is sufficiently low. The question is then on how to find a commodity that has a real return from just sitting there. There is a larger problem, though, with small denominations. How do you mint coins measured in cents when the commodity is, for example, gold? Either the coins need to be very small or they have very small commodity content, to the point that they become ... fiat money. Monetary policy also becomes tricky, as quite obviously temporary easing becomes difficult if it risks driving fiat money out.
But in the end, isn't a commodity like gold only valuable because people believe it is valuable? Gold, to take an extreme and popular case, has little intrinsic value, as I argued before, and is thus just another fiat currency. It is all a question of perception.