That's not what the word "fiat" means. A fiat is a decree. An order given by an authority. In currency terms, this usually means a decree given by a government

That's not what the word "fiat" means. A fiat is a decree. An order given by an authority. In currency terms, this usually means a decree given by a government that a certain currency will be used. It makes no sense to say "Bitcoin is fiat" and then to say it doesn't have any government or strong player behind it. It's one or the other.