I want anyone to show me that it is humanely possible to send an input key after receiving visual stimulus and for that to happen around 5/10 frames. In a game which has around 0.500ms/0.800ms delayed based on his distance to the servers.
A very important point indeed.
The average reaction time to visual stimulus is 250ms.
Add the server lag and you have almost a second, depending on your distance from the server.
Not taking into account PC lag, which varies depending on your monitor refresh rate and PC hardware.