Absolutely! But it would still be a big win for SteamOS - in terms of mainstream adoption, anyways - if popular games could be played on their OS.

They are able detect kernel level cheating by looking for things like suspicious kernel drivers being loaded and are able to detect some forms of hardware level cheating, things like special pcie cards for DMA can be detected by kernel level anticheat, more sophisticated hardware level cheats cant be detected by kernel level anticheat. to be clear this does not mean that there is 0 risk of malicious intent and behavior done with the kernel level anticheat, and also the security implications of extra code inherently running in kernel mode when it doesnt need to still exist, but to say that they nothings is wrong, they at least in theory are able to detect more cheats than a userspace level one, now if they are actually using their kernel level priveledges to detect those cheats that, a traditional userspace anticheat wouldnt be able to, is a diferent question