Except not everybody wants to carry gold.
They wouldn't have to. A gold standard simply means that whatever currency you have is fully redeemable in gold (or silver). You'd still carry paper bank notes and credit cards.
You don’t have to carry gold under a gold standard. You carry around paper receipts redeemable in gold. That’s what the dollar originally was. It was a weight of gold, equal to about 1/20th of an ounce. (Way back when the dollar was actually an ounce of silver)