Exactly. In addition, sometimes a good software "only" makes you save 1% of your time, but that 1% was a terrible burden that induced mental fatigue, made you take bad decisions, etc. It can even make a great Engineer stay when he would have left with the previous version.

While reading the article I was thinking the same thing. I can think of problems I've solved that directly affected 0% of our customers, but overloaded our customer support team.