alt Hacker NewsMovies are not projected using the scan and hold approach used by typical computer displays. They have a rotating shutter which blinks every frame at you multiple times. This both helps to hide the advance to the next frame but also greatly increases motion clarity despite the poor framerate.
But blinking a frame multiple times rather than once creates a double (or triple etc) image effect. To get optimal motion clarity which compensates Smooth Pursuit without double images, one would need to flash each frame once, as short as possible. But that's not feasible for 24 FPS because it would lead to intense flickering. It would be possible for higher frame rates though.