The ideas here are: pay close attention to your user's actual experience with your product; nuanced experience fixes can have big collateral benefits; there's a way to do that in the context of everything else. All good, from my perspective.

The caveat is that the author in this case is not that different from his users, who are other devs. He gets their experiences. The magic trick for dev is putting yourself in your user's experience when they really don't think like you. Non technical, kids, accountants, whatever. You really have to drop your assumptions and forget your investments and just see things the way they do. Empathy rules, but I feel it is hard to codify that as a skill. There's a big leap before tiny wins.

EDIT- to add, the signals to look at first are user complaints, and user's efficiency on tasks with your product, aka usability studies. Empathy informs your takeways from that.