Careful: negative price ≠ negative cost. Below zero prices are a market artifact usually.

The fact that this happens during peak HVAC use is a nice thing though.

And yes, we need intermittent industries, but the problem is, when you invest money in hardware, even to mine bitcoin (I would rather sell GPU time to train deep learning models personally) or to produce hydrogen, every hour not spent running your capital-intensive hardware is considered a cost that is not really compensated by energy price unless you run on donated hardware.