Eli5: your PC has different access levels a program can run at. This prevents a malicious or badly coded program from completely fucking your computer. Kernel level anti cheat runs at the lowest level access that exists under windows. It can do basically whatever it wants to your PC, and if a backdoor is coded in (happens way more than you’d think), it gives malware basically total access to your PC.
It isn’t safe, but its better than taking it off entirely.
Anyone who’s above average height or buys one of the mega cursed headrests that sticks out 4" is not keeping that thing in its factory state. If nothing else you’ll injure your neck from the constant contortion.