Is erveyone playing with killboxes?

Since i found this sub it looks to me like everyone is playing with killboxes. Is really everyone playing with killboxes or are the people playing with them just very proud of the meatgrinder they created? I never tried playing with them, i think they make the game to easy and are kind of exploiting the ai. They also kind of destroy the immersion for me. Instead i try to use the Environment to build Strategic defensive Positions. But i also dont play on the Hardest difficulty and maybe playing without a killbox is not viable when playing the game on extra Hard difficulties.