The short answer is (From what I have researched) most online shooters elevate the game into kernel (CS:GO as an example).
The idea behind it is that hacks for the game have to be written for each machine, cpu, gpu effect how the hack has to be loaded.
So this prevents mass sharing of said hack, and makes it easier for the mods to ban one or two people rather then 20k that have downloaded a old hack someone released.
They protect graphic files the same as script or damage values, as well seeing through walls is an advantage.
(I am not a programer and the info I am sharing came from someone who claimed to have hacked CS:GO and was explaining why he did it and why it is hard to do now.)