These fiat currencies are all considered ''legal tender''
and so is gold in the US states mentioned
Legal tender is a form of money that courts of law are required to recognize as satisfactory payment for any monetary debt. Each jurisdiction determines what is legal tender, but essentially it is anything which when offered ("tendered") in payment of a debt extinguishes the debt. There is no obligation on the creditor to accept the tendered payment, but the act of tendering the payment in legal tender discharges the debt.
So yes I can pay off a house or a car or a debt with my little gold coins in those states
