>Mouse clicks and distance are two of the most basic metrics. And straight forward. So why wouldn't you optimize there?

That's the McNamara fallacy: https://en.wikipedia.org/wiki/McNamara_fallacy Basically: enemy bodycount is easy to measure and thus you should optimize for it. Conversely if you can't measure it, it must not be important. The fallacy is that enemy body count is not wrong per se, but oversimplified.

I don't disagree with focusing on making most use-cases faster, but treating a human like a machine ignores things like error rates, understanding, lasting impressions, and ease of learning, which are important for users who have a choice in software. If you have vendor lock for your software, you don't need to optimize at all so it's kinda moot.