[kalos72]

Besides the symbolism, anything is worth what people will pay for it.

If I am the bossman in BumScrew Texas and I control the food, if I say a days food is worth 10g gold, then all of a sudden gold is worth something.

Same as if I say 10 Coke bottle caps are required for a days food.

Looking forward, gold/silver/oil backed currency is probably on someones list of things to do. Fiat currency is worthless, literally.

I do suppose, talking this out, if you control the food/oil you can have the locals find all the gold there is just by requiring it to buy food.