See the thing is you are ALL right. That's a happy ending right there! There are two powerful traditions within economic theory 1. that sees gold as a commodity and 2. that sees gold as a currency. The latest research on trying to track the gold price acknowledges BOTH traditions and argues that elements of both gold as a commodity and gold as a currency affect its pricing. See this eye-watering article (interestingly by Chinese scholars) on trying to explain gold price movements.