Apple doesn't ship stuff just because it's available; there has to be some appreciable value.

Faster refresh doesn't necessarily mean a better display. I suspect Apple's displays are higher quality than most competitors even if they max out at 120Hz.

Here are the specs for the latest MacBook Pros:

    16.2-inch (diagonal) Liquid Retina XDR display;1 3456-by-2234 native 
    resolution at 254 pixels per inch
 
    XDR (Extreme Dynamic Range)

    1,000,000:1 contrast ratio
    XDR brightness: 1000 nits sustained full-screen, 1600 nits peak2 (HDR content only)
    SDR brightness: 500 nits


    1 billion colors
    Wide color (P3)
    True Tone technology
    Refresh rates

    ProMotion technology for adaptive refresh rates up to 120Hz
    Fixed refresh rates: 47.95Hz, 48.00Hz, 50.00Hz, 59.94Hz, 60.00Hz

120hz is slow technology but those MBP displays are around the best you can get when you look the whole picture, notch aside.

Exactly. You can't just look at one aspect.

Is there any evidence that such high refresh rates provide any value, or are even detectable by human eyes?

In games with fast motion, 120hz vs 240hz is easily perceptible (outside first person shooters it’s not good to provide much value). I would be fine with 120hz for desktop work, but 60hz displays has been a gripe of mine about Macs for a long time. 120+hz was available on CRTs 25 years ago…

I can see benefits even while scrolling a webpage or moving windows around. It's very confortable.

This been said, I can remember CRTs at 60hz with side scrollers and demos at 60fps with perfect image stability while scrolling. You could read tiny texts scrolling up and down perfectly. This is not the case anymore with LCD panels...

Try to read a webpage while scrolling, impossible.

60hz or 120hz I would pay for a stable image in motion. It would bring tremendous confort.

Yes, blind tests have shown that users are easily able to discern between 60 vs 144hz.

This isn't really contested anywhere.

IMAX did tests back in the day with footage of a baseball being pitched directly at the camera. They found that the intensity of emotional response tailed off after 60hz. It's not that the higher frame rate isn't perceptible, but that raising the frame rate doesn't really have any appreciable impact unless people expect higher frame rates.

There's a notable difference between passively consumed content and interactive content.

We're fine with 24FPS for films and tv shows, but try that for an FPS and it's considered nigh unplayable. I remember when the line was "the human eye can't see past 30FPS" now it's at 60. The treadmill keeps going.

I know this isn't what you mean.. but I'm imagining someone blindfolded in a research lab testing this out...

Blindfolded person: "I can't see a difference!"