I keep seeing forecasts that cash payments are dying, and they will not be used in the future. The OED defines cash as "Money in coins or notes, as distinct from cheques, money orders, or credit." It may be probable that soon the use of coins and notes will not be commonplace for everyday transactions for the general population, but governments are busy creating gold coins for the wealthy to use as untraceable payment methods. In the UK, the government has even given tax advantages to users of its gold coins, including Sovereigns and Brittanias. A Brittania is currently worth over £1,000, so it is unlikely to be used in the purchase of a coffee, but they are being used for payments between countries, and for other larger settlements. No doubt some of those will be for illegal goods and services. They can also be used to reduce inheritance tax, as the value of a Britannia is fixed at £100 for the purposes of estate duty.

The interesting question relates to crypto-currencies. One wonders when some coins, such as Bitcoin for example, will be included in the definition of "cash".