Any interpolator produces some amount of artifacts.
These artifacts are present at calculated frames only. Source frames are not touched. So, the aim is to save all source frames at output.
24 > 60 fps interpolation gives 12 source frames and 48 interpolated frames in one second at output.
24 > 120 fps interpolatin gives 24 source + 96 interpolated.
In this example 120 fps is twice better as it has all source frames.
If you look at 72 fps interpolation it gives you 24 source + 48 interpolated frames in a second. It is all source frames at output and human eye will see them 24/72 = 1/3 of time.