Imagine the environmental impact of POW running on everyone's browser all the time globally just to use the internet. What is the point of having these gigawatt class hyperscale datacenters if we are still going to make clients run laps for every request?

Performance is the most important feature at some level. If an unauthenticated request from the public internet ties up your web server's CPU for more than a few hundred microseconds, you are eventually going to get screwed no matter how you slice it.