I had two clients from America I want offer graphics designing jobs for, I demanded my payment would be in BitcoinBTC or Ethereum. To my greatest dismay, they were dumfounded on what Bitcoin or Ethereum is. I am still suprised up to this very moment. 
Your clients does not represent the whole America so how come that you conclude about this by just your clients does not know about Bitcoin or ethereum? But i think there are many americans already Knew about Bitcoin but of course like the whole world there are smaller amount compared to those who have ideas.
But lets see couple years from now,Maybe your client will already have idea what this is and how convenient using crypto as payment.