I've long believed that the main point of client-side anti-cheat is to serve as security theater.

If the player sees "PROTECTED BY ACME ANTI-CHEAT" on the boot screen of a game, they're less likely to cry wolf when they get their ass kicked. At least, until they see a blatant example of hacking and lose all faith in the ability of the platform to protect them from it; from that point on, everyone better than them must be cheating from their perspective (speaking from firsthand experience here).

Given how infamously toxic and high-strung the LoL community is, I can only imagine that Riot's basically at the end of their rope here. If you read the original forum post, they sure make this sound like a Hail Mary. "Sorry, it's just what we have to do to make sure the game is fair."

Hilariously, they even undercut their own points in the FAQ:

Q: If Vanguard is so good, why do I still see cheats on VALORANT?

For starters, we do not action every cheat or account instantly. Every ban is like broadcasting a signal to the developer that their cheat has been detected and that they need to "update" it. In order to slow the progression of our "cheat arms race," we delay bans based on the sophistication and visibility of the cheat and cheater, respectively.

But also, cheaters gonna cheat. [Emphasis mine.] We've really driven our preventative layer as far as we can feasibly go without colliding with existing setups and hurting legitimate players. [Linux players aren't legitimate I guess?]

Also, they're apparently not bothering enabling Vanguard on OS X because apparently few people have actually developed cheats on it yet. Really tells you what's the more developer friendly platform, Linux or OS X, doesn't it? Or maybe the OS X market share is too small to care.

They do also mention using machine learning to detect cheating server-side but lament that it's not always enough information, and that cheat developers have added "humanization" elements that play more like humans.

My thought is... if a cheat doesn't make someone obviously better than a human player of a certain skill level, then what does it really matter? Congratulations, you made a bot that's indistinguishable from a human, thanks for padding our player numbers.

The real problem is that botters don't pay for microtransactions. And players who buy bot-leveled accounts probably don't spend a ton either. Why would they? They got everything unlocked for them, they didn't have to grind for it. That's all Riot really gives a shit about.