In this case there wouldn't be a single issuing entity: "the cryptocurrency would indeed be pegged to a basket of currencies". I had written about the idea of a stablecoin tied to a basket of currencies, e.g. J M Keynes' Bancor and the Word Currency Unit, a few years back.

> why not just have your balance be an entry in a regular database maintained by that entity? What exactly does the blockchain gain you here?

If it is controlled by a centralised organisation there would appear to be little point of "blockchain", but maybe as the article says "By introducing a level of decentralization to the governance of the project, Facebook may be able to avoid regulation related to it holding too much power over a global currency".