Riot, by simply existing and pursuing their mission to mine bitcoin, provides a valuable service by discovering the real price a kWh should cost. Since Riot will never overpay for electricity, (they'll simply scale back their use) and they'll happily gobble up as much as they can when electricity is "too cheap" they ensure that the amount of generation is constantly matched to the demand, adjusting for every conceivable variable in an economy in real-time. ERCOT and the consumers of the Texas grid also benefit from this hyper-efficient cost discovery system, every single second of every single day.
It's not just better than the stock market, it's capitalistic principles working exactly they way they've always dreamt of.