Anti-Cheats Opinion

They could do anti-cheat that would stop all cheaters, but they won't.
Why?
Because they have a much more money of dump people that get accidentally banned by overwatch and so.
And when they want more money they just make VAC wave, what that means? They will get some big cheat cracked like Aimware, Interwebz and so, they added them to the blacklist of signatures that aren't allowed by VAC and all users of these big cheat companies get VAC, and because they enjoy hacking they go and they purchase another account so they can continue after their cheat provider updated their cheat and this goes again and again.
They're letting cheaters cheat a lot, but when it's enough like when someone released way how to make nospread on any server (calc the random spread of bullets so you can bhop and shoot or whatever and still have 100% accuracy) they patch it within 2 days like nothing.