Quote from endsongs:
The question is at what rate of inflation will people stop using dollars, and start using gold, for purchases because of the convenience factor? People should know that in Zimbabwe a few years ago, individuals stopped using the currency for exchange, even though it was still in circulation. This was because the hassle of converting it the prices which were changing almost minute by minute was too much. So mucch of Zimbabwe started using gold, again.
A stable exchange rate is needed for money. Just like Zimbabwe, if one has to choose between using a steady 1 or 2 grams of gold per week for food, or an increasing amount of cash per week for food, the choice is obvious. My guess is it would only take a rate of a few percent per week for the switch to gold to start.