I had a thread about this a few weeks ago - nostr:note1ecdg2jsm3333uugw0wwwqtw7vzkpc6jn0ad24aa2e504vq7n4ezqewrfg0
It’s not as straightforward as you think. Imagine you sold your car or house and wanted to put the proceeds into Bitcoin rather than hold cash. Or you just got orangepilled and want to convert stock holdings.
Not everyone is already all out of fiat.