"The human eye can't tell the difference past 30 FPS" was literally just a thought-killing cliche repeated by console gamers getting into internet slapfights with PC gamers.
You can see the difference for yourself here on any 60hz monitor: http://www.30vs60fps.com/
In it, they have a segment on frame rate[2], where he mentions that the neurons can only fire about every 13ms, or about 75 FPS. But, the important point, they're not in sync like a computer screen is. This means the effective update rate for a group of neurons can be much less.
Even then, the problem is that eyes don't work like cameras or monitors. Our eyes don't work with "frames". Each receptor updates on its own time. It's easy to see that, if the updates are staggered, multiple sensors could perceive higher frame-rates, even if they can't individually.
However, there's another angle to this. Disregarding input lag, which is a very real phenomenon and is greatly shortened by higher refresh, higher refresh rate monitors are able to show more 'discrete' steps for anything that's in motion. Our eyes (and brains) perceive this as movement 'smoothness', even if they can't quite make out every single frame that's displayed.
You should try that yourself. Do a blind test.
The easiest way to show this is by wiggling your mouse around quickly on a computer screen.
At 30hz - you'll see the mouse teleporting around - hopping from spot to spot, but not moving. For example, if you stare in the middle, and jerk the mouse quickly to the right, you'll see the 4 or 5 spots where it rendered.
With 60hz, you'll see the 9 or 10 spots - and have a stronger illusion of movement.
With 120hz, it might even look as smooth as a real object flying across your screen.
It's as absurd as saying it's impossible to tell the difference between a 55" 720p display compared to a 4k one at a distance of 1 foot away.
Additionally, another thing I've noticed in the last decade is the very badly PWM-frequency-tuned LED headlights on some cars. Those engineers selected the wrong LED brightness and tuned it to terrible frequencies which leave flicker-trails when you look at or away from them.
Get those PWM frequencies above 500Hz please! Especially get above 200Hz with your LED frequencies at the very least.
Lower framerates are less noticeable in low light, which is another reason why films look acceptable.
*Talented animators/cartoonists can get away with lower framerates