Gold Standard is now part of the past. But USD is a true power for the US.
I am just thinking about this anecdote from BNP Paribas (French Bank):

• US had sanctions against Iran
• Europe had lifted sanctions for some part of the economy, therefore BNP Paribas settled some trades with Iran
• US Court convicted BNP for trading with Iran and extorted $9.6bn
  How did this happened? BNP cleared the trades in USD (dumb) therefore US Justice Department could fine them even if they respected their homeland laws.
  Crazy...