I think the point of the article is this: If people are like CPUs - if all CPUs are busy 100% all the time, then latency, as we all know, sucks, and processes

I think the point of the article is this: If people are like CPUs - if all CPUs are busy 100% all the time, then latency, as we all know, sucks, and processes may crash occasionally. You want decent latency, and avoid crashes, then keep the CPU usage below the ceiling level.