"Circulating supply is not a useless metric, neither is total supply."
OK, So I create a coin with a total number 10,000,000,000,000,000,000 (10 quintillion units). I'll call this "Quintillion Coin". I premine 9,999,999,999,999,000,000 units for myself. The market starts buying these at $US0.01c each. Therefore "Market cap" is $US0.01c * 10,000,000,000,000,000,000 = 100 Quadrillion US Dollars.
My coin now has a market cap 5,300 TIMES BIGGER than the GDP of the United States.
Market cap is therefore a useless metric in every respect for cryptocurrencies.
"You're argument is like saying the AUD doesn't fluctuate against USD (or any other currency) based on economic activity and other variables,"
My argument is not this at all. My argument is that your assuming all data is economic activity, which is an assumption. As per the above example I've provided, it's an assumption which can also be gamed.
