In the world of fiat money, gold has no face value and gold is not a payment method too. Now gold is just an investment.

Before 1971, the dollar was pegged to gold. Price of gold was $35 per ounce. So, gold price didn't float.

Traditional money has a face value. It applies to fiat money as well as fiduciary money. Bitcoin does not have a face value. Its value depends on demand and supply (like shares or other investments). At the same time bitcoin can be used as a payment instrument.

I think that is the main advantage of bitcoin: it comprises features of both investments and money. Thanks to that, the bitcoin eliminates the division between money and investments and makes investing available for everyone for every level of society.