Earlier quoted context omitted.
I'm gonna go out on a limb here and say maybe we should in general ban things that are a certain amount less energy efficient (say, 5x more wasteful) than the best technology we've achieved for a similar purpose so far. And progressively tax anything that's moderately more wasteful (say, 2x-5x). It's bad enough that we have cars on roads that are twice as wasteful as they could be, let alone a transaction processing…
No, please don't tax something because it is wasteful or not, but tax something based on how much resources it uses. In fact, tax the resource usage not the activity. Even an extremely efficient car uses a ton of energy to move around. New cars often have engines in the multiple hundred kW range, which is insane compared to any other appliance you own. If fossil fuels were taxed properly, that would discourage using/…
"Wasteful" = "using more resources than it genuinely needs". We're saying very, very similar things here. I don't find the difference between them significant enough to be worth arguing about honestly. I'm just suggesting an alternative that I think might be more viable, but if we go with your proposal, that's enough progress to make me happy.