Why are they obviously minuscule compared to crypto mining? I'm unpersuaded that the ecological problems caused by crypto mining net above zero, but in any case they are obviously minuscule.

That's true, still, we can find a more sustainable way of making banknotes I'm sure.

Edit: actually I'm not sure if that's true, are there reliable sources that we could rely on?

Obviously I stand by the rest of my statement (even if X is better than Y, that doesn't mean that we should oppose proposals to improve X)