It’s not about the cooling of the machines- Miners have wholesale per hour pricing for electricity, and heat wave means higher A/C use, so miners get much higher prices and they power machines off to remain economical.

At the same time this process reinforces the energy grid, by selling extra electricity to Bitcoin miners- more power generation can come online, and during peak demand hours (hot days using A/C) the miners power off and the people enjoy a huge buffer for energy demand.

Bitcoin is pretty great for humanity.