"Generally no one is “consuming” gold bullion."
Huh? Gold bullion is an input to hundreds of industrial processes. If it weren't, why would gold have any value?
Why would gold, something that’s had value for thousands of years prior to the Industrial Revolution, have any value?
That's not consumption as it applies to sales tax rules. In almost every jurisdiction, raw materials and inventory purchased for resale or industrial processing are exempt from sales tax.