Funnily enough the Venezuelans and Argentinians solve the infungibility of their national currencies with US dollar-denominated offshore accounts. The US dollar is also the national currency of two other Latin American countries. Call me an extremist if you like, but I think the US is more likely to regulate Bitcoin into near irrelevance (guess what, AML laws can be applied to exchanges and Silicon Valley companies accepting BTC too!) than they are to make it difficult for Banco Central del Ecuador to replenish its dollar reserves. And Russian oligarchs facing sanctions are more likely to keep their money in Russian banks than in the crypocurrency their own government intends to ban http://rt.com/business/187440-bitcoin-ban-russia-cryptocurre...

How many people have left the informal economy to transact exclusively in Bitcoins?

Isn't a currency fungible by definition - a dollar is a dollar is a dollar? And we are getting away from the question I asked - what are the advantages of using Bitcoins, advantages that average people actually care about today and that are not offset by disadvantages of using Bitcoins.