One issue that arises in the discussion of cashlessness is whether merchants have to accept legal tender or not. In the U.S. there is no Federal statute mandating that a private business, a person or an organization must accept currency or coins as for payment for goods and/or services. Similarly, in the U.K. where only coins valued 1 pound Sterling and 2 pounds Sterling are legal tender in unlimited amounts you cannot force a shop to accept them. Legal tender is only legal tender for debts incurred: you cannot force someone to incur a debt (so you cannot force a shop to sell you something for cash). A shop is free to enforce any conditions it likes (within the boundaries of the law) with customers since when you buy a coffee from the coffee shop, you are entering in to a private contract. Our good friend Leo van Hove made a very good presentation about this, called When Will Electronic Money Be Legal Tender? at the 7th annual Digital Money Forum and you can download it here. It’s well worth a look if you’re new to the topic.
Meanwhile, Microsoft has abandoned fiat currency altogether for its marketplace. You can only buy songs for their new Zune music player using Microsoft points. I remember giving a presentation many years ago in which I said that the transition to digital money would lead not to the one world currency beloved of science fiction writers, but to many currencies because the cost of issuing a new currency in the digital world is essentially zero.
My opinions are my own (I think) and are presented solely in my capacity as an interested member of the general public. [posted with ecto]