Depending on the implementation, client side anticheat isn’t needed at all. Take the game Speedrunners for example. There is zero need for the server to do anything other than accept player inputs, process them, and return them to the clients.

So if coded correctly, where the server trusts nothing and does the math itself, it is impossible to cheat while having zero anticheat on the client.

And that’s without there being any additional cost.

I’ve been working on a PvP game for the last few months.

Visibility checks aren’t needed in all cases. Most RTS/2D/2.5D games don’t have this problem, or it is minimal.

For games that do need them, they tend to be AAA FPS, which have the budget to make simple changes like lag compensation.