Camera focus regions allow map developers to force the game camera to target particular positions in the map, with varying zoom levels and strengths. Not only does this allow the map developer to ensure that something in particular is seen by the player (irrespective of their screen resolution), it allows certain parts of maps to be tied with a particular "focus point", which is great for indoor/cave maps https://www.youtube.com/watch?v=qhEt71_bvpM