I feel as though this variable might be self-explanatory, but what does it do, exactly? Are there any quirks to it?

0, 0, 0 is where the server stores many thousands of entities, and going there will often cause a lot of client side lag for the player if the terrain is not raised enough to prevent it. this option prevents bases from spawning there and thereby reducing foot traffic in that area. its set to 200 by default so that 0, 0, 0 is out of render distance.