Animation is a trick that your unconscience mind plays on your conscience mind, you begin being able to see motion from an animated scene with a very low frame rate and see improvements until the frame rate becomes reasonably high.
Movies have (traditionally) been captured and displayed at 24fps for two main reasons; higher framerates would require far more film which has (historically) been very expensive, and the natural motion blur that occurs on film makes the (relatively) low framerate less noticeable.
3D games have no natural blur, and often have (seemingly) rapid camera angle changes because they're being manipulated in real time; on top of this the videogame animation lifecycle works on updating the world model (including physics, animation and AI) at every frame, and framerate drops can cause problems.
