Comment by estebank

You're forgetting about the shutter angle. A large shutter angle will have a lot of motion blur and feel fluid even at a low frame rate, while a small shutter angle will make movement feel stilted but every frame will be fully legible, very useful for caothic scenes. Saving private Ryan, for example, used a small shutter angle. And until digital, you were restricted to a shutter angle of 180, which meant that very fast moving elements would still jump from frame to frame in between exposures.