Good point. However, approaching this problem from “YAGNI” point of view is a bit misleading, I think. If you are not going to need the timestamp, you shouldn’t add it to your code base.

I don't agree it was a good point. It sounds like the blog author missed a requirement a few times, and after getting repeatedly burned in the requirements gathering stage he now overcompensates previous failing with I'll advised usages of timestamps instead of booleans.

YAGNI is always true. Always. The author's point, even when timestamps end up being required, are moot.

Also, if state changes are required them you don't tack on a timestamp to a row. You instead track events, including switching stuff on and off.

I feel this blog post is bad advise fueled by trauma.