Linux

That doesn't seem relevant to the discussion at hand. The question is "is it better if something happens earlier" and if, as you say, the median reaction time is 273 ms, that means that median player a will consistently be 3 ms faster than median player b if they react to the same event all else being equal. 273 ms will beat a total of 276 ms every time in a race to react.

Latency is compounding. There's no point where less latency is not better. It's completely irrelevant how fast my reaction time is, as removing 3ms from the system latency allows me to start reacting 3ms earlier.

Edit: I do agree though, that 3ms more or less is not a deal breaker. I'be been playing on Wayland for many years. But not being a deal breaker does not mean it's not a big deal.

There’s a big difference between when you mentally react to something and when you can physically react no?

That's purely reaction with not even a countdown, plus whatever lag introduced by the browser, display, mouse or touch, phone or pc.

With music games you aren't waiting an arbitrary amount of time, you are matching a tempo and moving ahead of the actual sound to land on the correct time, almost certainly with visual cues that let you read ahead, and getting scored on how perfect it was. More often than not it will be a song fully memorized and the player is trying to push the limits of how close a human can get to perfection. There is still latency in rendering and display, audio playback, input, etc. and you can end up with visual cues being offset, input being offset by a different amount and direction, and as a result scoring being incorrect.

If a single human can't do that, then how would an orchestra ever have worked? Its different movements and visual cues but basically the same thing: Match timing with the conductor and between memorization, practice, and the sheet music you get your read ahead of how to move. I've never taken dance lessons but it surely comes down to the same fundamentals.