To me, there's a big difference. I accidently forgot to set the refresh rate in Nvidia control panel to 144Hz after reinstalling the driver at one time.
At first I couldn't figure out what was wrong with my game. It was nowhere near as smooth as it usually was, everything felt kinda choppy or as if frames were dropping. It felt completely wrong. The image was still great, but the way it felt was all wrong and unpleasant.
Then I finally realized my refresh rate was set to 60Hz - setting it back to 144Hz again, instantly rectified everything that felt wrong, and it showed - to me at least - how much of a difference there is when using a high refresh rate monitor.
It depends on what games you play. I don't really need the 144Hz when I'm playing Transport Fever 2 for instance.
Or if your graphics card can't push enough fps, then it doesn't really improve over a monitor with a lower refresh rate.
But as someone already stated in this thread, even moving things around quickly on desktop will look very different - way more smooth and fluid at higher refresh rates. That may not seem very important, but it is a good way to visualize the differences between refresh rates.
I can never go back from high refresh rates. Before I had a 144Hz monitor, I just thought it would be nice to have one, but I was very happy at 60Hz. Then I bought a new monitor, and now I 'm addicted