Nope, not crazy. 24fps has long been the standard for "as smooth as real life" motion in the movie & TV industries. The human eye needs a minimum of about 12 fps to perceive images as smooth motion. I used to do 2D Javascript games at 15 fps and while it clearly wasn't cinema-quality motion, it was perfectly playable.

The reason 60fps has become such a buzzword lately is because most laptop & phone screens refresh at 60Hz, and so you physically can't do better than that. At that frame rate, the electronics of the display become the bottleneck rather than your CPU/GPU power, and most engineers would rather say some engineer is the bottleneck rather than deal with the fuzziness of human perception.