I mean, people are dumb.
Anti cheats are as much a marketing ploy as they're actual anti cheats. People believe everyone is cheating so it must be true. People believe nobody bypasses the FACEIT anti cheat so it must be true. Neither of those are correct.
Riot revels in this by marketing their anti cheat, but there are always going to be cheaters. And sooner or later we will have vulnerabilities in their kernel spyware. I much rather face a few cheaters here and there (which is not as common as people make it to be on high trust factor).
You think tournament organizers or pro players know the first thing about anti cheats? They buy the marketing just like everybody else.
The marketing works because online games get destroyed by cheats. Losing in online games can be full of “feel bad” moments, even without cheaters (network issues, cheesy tactics, balance issues). To think that your opponent won because they outright cheated just makes you wanna quit.
I’ve seen so many players saying “look you can own my entire pc just please eliminate the cheating.”
It would be great to see more of a web of trust thing instead of invasive anti cheat. That would make it harder for people to get into the games in the first place though so I don’t know if developers would really want to go that way.