It could definitely help a lot of unbanked people. But that seems to be a nice benefit rather than the core mission.
Yes, for unbanked people who, according to the Facebook FAQ, set up an account using a state-issued ID and jump through a bunch of other hoops that are the same you would need for a bank account.
Assuming you can buy/sell it with better fees/rates. It's bound to be better than some and worse than others.