Earlier quoted context omitted.
prices, of all goods, inflate exponentially the relative value of specific goods fluctuates within a small constant in the long run, the exponential dominates the linear ---- thus the price of gold is a yardstick of the exponential inflation of prices, irrespective of the relative fluctuations of gold vs food vs energy
In an economy, gold is just one more good. Sure, we could use it as an inflation index. Or we could use gasoline, or new cars, or eggs, or any of a million other things. Why should we use gold as opposed to all those other things? Or, here's an idea, maybe we should use a weighted index of several of those things as a measure, in order to prevent misleading data from the fluctuations in the price of any one item?
That's done already. More useful: such index as a ratio of wages. Say, [price of standardized basket of commodities] / minimum wage.
That would tell you how many # of paid work needed to (for example) fill a shopping cart with a week's worth of food + heating / powering one's home over that time.
("minimum wage" = applies to folks scraping by in low-paid jobs. Higher earners are living the good life anyway, imho).