While the human eye can technically only make OUT 30 (60 interlaced) frames per second, the human IS capable of noticing -changes- in Framerate.
The point for having high frame rate per second is that a drop from 100 to 50 is a LOT LESS noticable then from 72 or 60, down to 20-30.
The human eye might not be able to SEE all the images, but it's a matter of perception to -change.-
There's no reason not to have fps_max at 100.
Someone who stares at a monitor with a 100Hz refresh rate all day will notice a very painful difference when the refresh rate is dropped down to 72Hz or 60Hz.