Quoted from robotron911:
And, btw, there is legal precedent that you HAVE to take cash. Read the bill itself... it is says "This note is legal tender for all debts, public and private" Cashless society would be dire for the U.S. government as it would move toward a unified currency. The U.S. makes money simply because the dollar is the most stable currency in the world.
Sorry, you have not read it correctly. There is no Federal requirement to take cash. Massachusetts has some law on the books for it, but I am not familiar with it.
This statute means that all United States money as identified above is a valid and legal offer of payment for debts when tendered to a creditor. There is, however, no Federal statute mandating that a private business, a person, or an organization must accept currency or coins as payment for goods or services. Private businesses are free to develop their own policies on whether to accept cash unless there is a state law which says otherwise.
As far as position, they may not have stated it publicly, but the government preferes electronic transactions. It is easier for them to track flows and do forensics when needed, the mint isn't free to operate, and counterfeiting is always an issue.