Why 'stable coins' are no answer to bitcoin's instability

New cryptocurrencies such as Tether may be pegged to the dollar, but they have big flaws

While the mania for cryptocurrencies may have peaked, new units continue to be announced, seemingly by the day. Prominent among the new arrivals are so-called "stable coins." Bearing names such as Tether, Basis, and Saga, their value is rigidly tied to the dollar, the euro, or a basket of national currencies.

It's easy to see the appeal of these units. Viable monies provide a reliable means of payment, unit of account, and store of value. But conventional cryptocurrencies, such as bitcoin, trade at wildly fluctuating prices, which means that their purchasing power - their command over goods and services - is highly unstable. Hence they are unattractive as units of account.