Guess who has all their money in Gold?
Aside from being a pretty and maleable metal, I do not understand why Gold is valued any more highly than Bitcoins aside from the history of trading. Gold is no more 'backed' than Bitcoins, you can't eat either at the end of the day.
Imagine your DR Who from the TV show with a time machine. You can go back anytime you want in 4,000 years but you don't know which year. What do you bring as a currency to trade?