So a cryptocurrency that is more currency than crypto? Again, back to the argument that the market is the same as in-game currency, store gift cards, Chuck-E-Cheese tokens, etc. Let's be honest, most of the hype around cryptocurrency is for speculation and not as a legitimate means of exchange. Normal money works fine for means-of-exchange barring a few exceptions e.g. capital flight, money laundering, generally esca…
As such, stablecoins have entirely different requirements and properties than regular cryptocurrencies; for one, you usually want one big well-known entity backing them, because for the stablecoin to be stable, someone needs to back the coin with liquidity.
“Liquidity” is something Facebook obviously has more of than most others, so they’re an obvious party to build a stablecoin.
(Really, though, the best stablecoin for USD, would actually be run by the US government. There’s no reason for them not to do so, and no reason for people to reject them doing so. One could even interpret running a wrapped-USD stablecoin on any popular-in-the-US blockchain as being an obligation of the US Mint, given their mission. They’re currently failing to “print money” for these US markets!)