https://libra.org/en-US/white-paper/#the-libra-blockchain This is how you fix fiat, and render Bitcoin moot in the process. Not to be an alarmist, but we should all be very worried.
Before Blockstream, we used to take pride that Bitcoin is cheaper and faster than fiat. But the availability and convenience were just tools, the point was freedom from governments.
Now you can have BETTER availability and convenience with fiat, so why would the mainstream adopt Bitcoin? It will only serve the few of us who truly care about freedom.