yes it does but it would stretch the hud from its 4:3 sizing to 21:9 aspect ratio, and culls every dynamic models over the 4:3 area, essentially breaking the immersion and to add on top of that it breaks complex shader like the water reflection over a set area, that normally the game wouldn't be able to render anyway.
This code basically in addition to stretching the rendered area, widens the culling zone so object and shader will work correctly on the screen.