I read the article as an unreasonably deep dive into something that few people care about as much as the author. I certainly don’t, but that’s what makes it good. That’s perfect for HN.
Not disagreeing, but you might be surprised at how widespread the interest in easing is. In my experience, easing is a major topic of debate whenever people are discussing the look and feel of animations.
Often people just argue over the proper parameters for the same old functions, but that's all they have available. Their arguments use lots of ambiguous human terminology like snappiness, surprise, anticipation, sluggishness, etc. that don't cleanly map to specific parameters.
Adjusting easing can produce dramatically different results in how we feel about something. It triggers our hindbrain. We want to pounce on the mouse, or block the incoming rock, or whatever, I guess? Try going in for a handshake a little faster or slower than usual and see what happens...
It didn't seem unreasonably deep at all. It was long, sure, but it seemed to only scratch the surface of the topics it was discussing. That was sort of my point in bringing up the css function - it is itself incredibly bare-bones, but just describing it's usage would have covered more ground imo.
"Unreasonably deep" is a relative term. Certainly deeper than I care to go. But sure, it could be unreasonably deeper.
Every time I have used animation my approach has been to treat it as frosting to be used sparingly. As such I would be much more attracted to simple/supported modes (that someone else will be interested in keeping functional) than I would be to obsessing over physics realism. But I am also a UI caveman with no taste, so there's that.