Perhaps Cash is King
Another reason to use cash: Tax Hitman to Track Your Spending:
Up to two million people are to have their credit files secretly checked under a crackdown on tax evasion to be unveiled by George Osborne to help raise another £10 billion.
I have always thought that the push to get rid of cash was in order to do give the government more ways to track your spending habits and invade citizen's privacy. Since the US seems to be turning into Europe, I won't be surprised to see this happening here in the near future.