The USD is backed by a government with a $1 trillion+/yr military that consists of ICBMs, aircraft carriers, stealth bombers, etc. Gold has some limited industrial uses. Equity shares are backed by corporations with current or future expected earnings. What is bit coin backed by?
The USD is backed by a government that is 20 trillion dollars in debt, with an inflation rate of 2% and forecasted to climb as the government regularly prints more money as and when they see fit. Only about 10% of the world's gold is used by industry - the price is artificially inflated because it is a ponzi scheme by your definition.