That only works in a perfect world where the public makes a collective risk assesment that is accurate. In reality, that does not happen. A single person might

That only works in a perfect world where the public makes a collective risk assesment that is accurate. In reality, that does not happen. A single person might use Libra because it is useful for them, and one more user of Libra will not change much. However, it is difficult to assess the risks that could come with FB having control over millions of people's transactions, and then factor that in your individual decision. And that assumes that people know what can go wrong with monetary policy, which is far from reality. To make an analogy... "If a country's citizens chose to use opioids for pain management, it must be because they found it useful, and the country should not have permission to prevent it."