Unlike the NYT, you left out what is arguably the most important point:

“But the messaging companies are likely to face many of the same regulatory and technological hurdles that have kept Bitcoin from going mainstream. The lack of a central authority over cryptocurrencies — a government or a bank — has made them useful to criminals and scammers, and the designs of the computer networks that manage them make it hard to handle significant numbers of transactions.”

How do you think the US will manage its $20 trillion debt if Facebook became more powerful that the Fed? Who will set the exchange rate between the dollar and the yuan? Who will set interest rates?