Is an electron a particle or a wave? From a trading standpoint gold sometimes acts like a currency and sometimes like a commodity. Does the distinction even matter?
Various precious metals in the past have been used in coinage, and at times certain currency issuers have promised to exchange their currency for gold at a fixed rate, but at no time has gold been a currency. And yes the distinction matters -- goods do not buy goods. Goods buy money, money buys goods. Money, as a definition, should not be producable through the application of labour
"The gold specie standard arose from the widespread acceptance of gold as currency.[7] Various commodities have been used as money; typically, the one that loses the least value over time becomes the accepted form.[8] The use of gold as money began thousands of years ago in Asia Minor."
