Perhaps this is a bit of a "chicken or the egg" dilemma. These two variables are recursive. As new stables are minted, the assumption is that investors are getting ready to deploy into crypto. But as crypto goes up and investors take profit into stables, USDT + USDC should also rise. Additionally, stablecoin market cap could rise in the short-term during risk-off periods as investors take chips off the table and move to "cash", which is probably what happened in Q1'22 while crypto was falling. It's an interesting metric to watch, but by no means the "end all, be all". This is why I pay attention to a bunch of different dynamics and then come to a conclusion based on the weight of the evidence. All else being equal, bulls are rooting for both of these lines to go up.