Is that still true in modern times with more people, but also better technologies? They make gold notes now that are 1/1000th an oz. Two of those would get you lunch. Also...if it was the main source of currency, wouldn't the value go up to where you would need very little (example - $15,000 an oz)?

I'd even guess you could keep it in a form of bank and then have a debit card you could use where most items were tiny tiny fractions of an oz. Is it still too little gold at that point?

I'm not suggesting a gold standard btw...just curious. I'd also point out that it might be crazy, but our current system seems incredibly risky and many nations have had their currency collapse through over supply. I don't think a perfect solution exists here.