What are you talking about? This is only for testing purposes. Recording video at 60 fps will give you the ability to resolve down to 17 ms intervals. When we are talking about human response times then 17 ms should give us enough resolution in most cases. What is so strange or funny about that?
And if you want to simplify things even further, you can simply state how many frames it took for the input to get to the screen. Hopefully it is within 2 frames since the input could have come a fraction of a second before the next frame was displayed in which case there would have been no way to respond in that frame.
BTW most TVs give you a "Gaming Mode" option where they turn off advanced processing since that usually delays the output by one or more frames. It's enough of an issue that they had to give a special mode for playing games.
Also, the notion that the human can only respond in 200 to 250 ms doesn't really apply in these cases because if you for instance record guitar into a computer and there is more than 20ms delay it becomes very distracting. It's about playing the string and expecting it to sound almost immediately. Even the slightest delay will throw you off. Now gaming isn't quite at that level but still, the threshold is much lower than 200 ms.