Unless people are far more sensitive than I am, I don't see how >60Hz is needed for a desktop workstation environment. High frame rate is really only noticeable for very fast reaction time gaming.
4K 120Hz may be noticeable if editing ultra high frame rate video on a video editing workstation, but if you are a video production crew with a camera capable of recording at that framerate, you probably already know that.
60Hz is really noticeable when you’ve been using 120Hz even for a few minutes. 120Hz feels a lot less tiring and work in a terminal, editor and websites is just a lot smoother.
It's immediately noticeable when scrolling in a browser, dragging stuff around or just moving the mouse. If you haven't seen it in person, go to an Apple store and do a quick comparison between the Macbook Pro (120hz) and the Air (60hz), or iPad vs iPad Pro. They're always next to each other.
4K 120Hz may be noticeable if editing ultra high frame rate video on a video editing workstation, but if you are a video production crew with a camera capable of recording at that framerate, you probably already know that.