Can you imagine what chaos we'd have if we didn't have the USD is mandatory in the US. Evey-thing would be ten time harder and take much longer, our days would be filled with negotiating and bartering.
Now with Cryptos we will see some flexibility but we still need the Dollar for now until there is a Defacto or Mandatory Standard which looks like it might be Bitcoin.
I have nothing against the Dollar. It serves a purpose for now but we will evolve past it sooner or later.
It does certainly serve a purpose, I agree.