Google has begun scoring how fast a site feels, and the trade has taken to it the way we take to any new number.
The underlying idea is a good one. Core Web Vitals measure things that genuinely matter to a person. How long until something appears. How long until you can actually use it. Whether the page shifts under your thumb while you are trying to press something, which is one of the small daily indignities of modern life.
These are real. I have no argument with the metrics. My argument is with what we tend to do to a metric once it can be scored.
Within a month or so, a question about experience had become a leaderboard. We start optimising for the number rather than the feeling. I have watched a site made a little worse for the person using it so that the green circle would climb, because the circle is easy to show a client and the feeling is not.
That is Goodhart's old warning, and I walk into it as readily as anyone. When a measure becomes a target it stops being a good measure. The score stood in for the experience. Chase the stand-in long enough and you will quietly trade away the thing it was meant to represent.
So make it fast, by all means. Fast is a kind of respect, and I have believed that since a ten-foot printer taught me what waiting costs. I only want to keep track of which one is the scoreboard and which one is the game.