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. 
I do not know the age of your clients but the awareness factor seems to be most present among those that are relatively young, so if your clients were outside that demographic group it makes sense they have never heard of bitcoin, this is why I have always thought that the adoption of bitcoin will take a long time as older generations are simply not interested in bitcoin, so we will need for time for that generation to be replaced and for those that are young now to take their place before bitcoin becomes as popular as we believe it deserves.