I suspect that a lot of that is for the sake of client side prediction: if an enemy runs out from behind a wall, you want as little delay as possible between it

I suspect that a lot of that is for the sake of client side prediction: if an enemy runs out from behind a wall, you want as little delay as possible between it happening and the player seeing it in order to react. Cheaters love it, but it does help with the illusion that everyone is playing in the same game world in real-time with no delays