Grain-based valuation

I think it is interesting (and wise) that the valuation of their monetary units was based on measures of grain. Payment for any goods or services could be calculated in terms of how many meals could be provided by the payment, thus everything was valued relative to how much people could be fed. They may trade in silver and gold but a job or an item for sale was essentially valued at a certain number of meals—easy for the producer to determine if it was worth their effort to produce.