Unlike what some answers say the price of Bitcoin is not in fiat dollars but in ‘stable’ coins - USDT,USDC…
Most of the current flow of value is from fiat currency -> to ‘stable’ coins -> to Bitcoin.
If even a small fraction of the flow goes the other way from Bitcoin -> to ‘stable’ coins -> to fiat, the crypto exchanges can not fulfill the promise of returning the amount in fiat. To find why is that, check -
The danger in the stable coins (thought experiments and the real price of Bitcoin)