Earlier quoted context omitted.
Luna crashed because people lost trust in it. The only reason people have trust in BTC is because other people have trust in it. If that ever changed, there is no actual use for a BTC, and they are thus intrinsically worthless. Fiat currency has the backing of a government. The government demands certain payments of this currency in order to own land, and also for some extra rights like mineral extraction, fishing li…
Fiat currency does not actually have the backing of a government. What could the UK do when the pound peg broke? Nothing but lose enormous amounts of money trying to hold it.
Want to own a house? Even if you buy it with bitcoin, you're going to need fiat to pay for the property tax bill.
Get paid wages? Even if you get paid in bitcoin, you still need fiat to pay the income tax bill.
Sell something? Even if you sold it for bitcoin, you still need fiat to pay the sales tax.