Thank you for reading and adding to the discourse.
Your points are quite right. But without launching into an overly technical debate on why I often choose to keep my articles technically as simple as possible, consider this:
Facebook will run a ‘central bank’ of sorts to manage circulation of its coins. It will have the right to peg the value of its coin to something, implement ‘monetary policies’ to maintain the stability of its value, maintain deposit ledgers of other institutions holding it for users in escrow or deposit, and all the other things that comes along with billions of users and many crypto exchanges and 3rd party institutions willing to hold and transact it. (Maybe even issue debenture notes of some sort to the public denominated in FB coins…)
Facebook may never become a country of course, but if it controls a widely used digital currency it will have to run similar functions to what a central bank does.