So, trying in good faith to understand, isn't the problem that the output in this case is physical, while Bitcoin's energy-to-money output is digital?

Why is that a problem? The price for Aluminium is more stable than the price of bitcoin.

I mean, you tell me. I don't mean to sound snarky. But it seemed to be your point that existing processes which turn energy into money are a hindrance to clean energy investments. The previous commenter offered an example of aluminum smelting. Which is not exactly what I meant, because I was being more literal when I was talking about an energy-into-money process, and that example appears to really mean energy-to-aluminum-to-money. I understood this example to mean that the reason other existing "energy-to-money" processes have been a hindrance to clean energy investments is that they have byproducts which negate clean efforts. In contrast to this, renewable crypto mining has no physical byproducts. Dunno if I misunderstood something.