About 70 millions of people owning Bitcoin. I can´t even imagine how many people could use Facebook coin when starts.
So it would be pretty easy to overpower Bitcoin.
Well,,, I used Facebook for many years, same as google, but I never bought anything for my google wallets or facebook wallets. I think a lot of people should be wary of FB now about their personal data and they will not just enter anything anymore with the worry of the safety of their information. Facebook coin is stupid. You think the marketplaces with blockchain will now add FB coin?