This website does things a poor justice and doesn't seem very accurate. For example, I tried this on my linux work computer (which doesn't offer vsync, or a graphics card) and compared it to my gaming pc. The non-vsync version looked much better than the vsynced version.

I went outside and took a 4k video at 24fps and played it back. It looks smooth as butter, just like a movie. Then I took the same video, but recorded at 60fps and re-encoded it in 24fps. It looks like the example on this website, where it looks jumpy.

I assume this is because of motion blur.