You may see the difference in quantity if you will follow a moving object with your eyes

In real world if you follow an object it's obviously not blurry at all

Let's say we are looking at a moving 40px circle
In 60FPS an object moving on 480px/second will jump by 8px every frame. The circle remains perfectly same, but as your eyes are following its position continuously, for your eyes it will be blurred between those 8 pixels, a whole 1/5 of the circle.
In 240fps the circle will be blurred by 2px, much less.

The same way you can differ a clean image on a screen from the same blurred image, you can differ the higher-frequirency moving image from a lower-frequirency one.

This also breaks eye's ability to properly follow the object, which breaks the immersion and may be felt by an average human without any extra tools