Cause you want to have zones. For zones you need to have some sort of array that will store each zone and then load if conditions are met. So if you'd have object as json, then you could put all objects in to arrays at their right positions, and then load them when player is entering that zone, while removing the old ones.
megatronx Good point, I wouldn't call "All objects" sometimes it makes me to think to load the whole objects in all zones. I understand about your idea, we definetly need this feature.