Can anyone explain what the point of a pegged cryptocurrency is? Since you are dependent on the issuing entity to honour the stated peg, why not just have your balance be an entry in a regular database maintained by that entity? What exactly does the blockchain gain you here? One thing it does _not_ get you is censorship resistance. If the central authority wants to take away coins from a wallet, all it needs to do i…
As for the value of blockchain here, there is absolutely none. Facebook is creating a currency and labeling it a cryptocurrency which denotes the use of a blockchain, when in reality considering they're the central issuing authority of the currency and are the ones who determine it's value/inflation rate (i.e. pegging as you rightly described). Therefore using a blockchain for decentralized settlement and provenance here serves absolutely no real purpose and you are correct in pointing out that they can just keep everything in a database (which is likely what they will actually do).