What irritates me is when games that don't even benefit from anti-cheat require it. Helldivers 2, for example. My dudes, it's a co-op game. My teammates and I are all on the same side! Moreover, the vast majority of people are gonna play with their friends, not randoms. And if your friend is using a cheat and it bothers you, you just ask him to stop. There's no reason for a game like Helldivers 2 to require anti-cheat at all, let alone the rootkit variety. And yet...
Elden Ring: Nightreign is also a co-op PvE game that has anti-cheating in it. The most common way people cheat is by fudging then items equipped to their character that slightly alter their stats and abilities. Since the game is rouge-like and all of your character information and equipment you can assign before entering the game is handled locally then all it takes is editing your save file which the game and server have no way of (or makes no effort to) detect.
Also, after a brief period, all of the cheaters disappeared because just repeatedly winning a PvE game get boring.
The best games with anti-cheat have an option to launch without using it, but just restrict what game types you can play. Playing with friends should be allowed without anti-cheat.
Yep. I've seen quite a few free-to-play gacha games of the "Dress up your pretty princess in cool clothes and do cute activities in a relaxing, no-stress world." variety that have serious anticheat. There's no leaderboard, no multiplayer, it's totally singleplayer.
Why the serious anticheat? To try to prevent you from cheating your way to possession of all the cool clothes for your pretty princess.
It's also bad with games that have been sucked into the live service hell-vortex. I can't fire up a quick game of Madden against the CPU because EA has turned Madden into a multiplayer lootbox casino, so they chuck Linux-blocking anti-cheat on the whole damn thing, single-player and all.
The super invasive kernel-mode variants (that is, the sort that's in Valorant) flat out fail, and surely always will. It's my (perhaps mistaken) understanding that with some others (like Easy Anti Cheat), it's a choice made by the game dev as to whether running in Wine/Proton will be permitted or not.
