I’m willing to bet that the value of an ad impression correlates pretty well with the relative compute power of the device. But, sites don’t generally restrict/

I’m willing to bet that the value of an ad impression correlates pretty well with the relative compute power of the device. But, sites don’t generally restrict/reserve content for, e.g. Android/iPhone users because they are more/less valuable to advertisers. The premise is that opt-in mining can be used as an efficient micropayment. Any new technology can be used toward dystopian ends, or not, so it’s not a reflection at all on the merit of the idea.