think about the gap between frames, 30hz is 33.3ms frame time, 60hz is 16.67ms, 90hz is 11.1ms, 120 is 8.33ms, 144hz is 6.94ms. YOu effectively have diminishing returns due to the frame time difference. The difference between 30hz and 60 is 16.67ms, the gap between 60 and 90hz(same size gap) is 5.56ms, or only 1/3 of the reduction. So while seeing the 16.67ms gap between 30 and 60hz is easy, and seeing the gap 8.3ms gap between 60 and 120hz is easy, the 1.4ms gap between 120 and 144 is extremely small and by comparison an extremely small improvement. It's also why 165hz is just as pointless, not least because the screens that 'offered' it were just overclocked and many seemingly didn't actually achieve those rated speeds without problems and the 200hz screens with a full 1.94ms advantage over 144hz was a tiny improvement (though not bad in terms of percentage), and the 200hz screens were even less available, even more overpriced and failed even more often.
Without question 120hz screens are better than 60hz. But this is a youtube video, it's probably only running 30fps and not even 60fps, so all should realistically look about the same on camera. They might look a touch sharper due to motion blur but that will be very hard to tell in a video. the video is just of him reacting and if about if HE can see the difference, the video isn't supposed to be showing you the difference itself to judge for yourself.