The advantage that the Dollar has over Bitcoin is that when dealing with the US Government, it requires dollars to be used. So the banks get FDIC insurance on

The advantage that the Dollar has over Bitcoin is that when dealing with the US Government, it requires dollars to be used. So the banks get FDIC insurance on US Currency deposits, and taxes to the government must be paid in dollars. So in essence, there's a legal requirement to use dollars when dealing with the federal government. So while the dollar is technically currency by fiat, it's also currency by legislation.