Of course immersion is important but so is positionnal accuracy, I mean in games, what you hear is related to what you see on the screen not the position of your own head (except in VR where it's already taken care of), hence the immersion. Your ears and eyes are in sync. If the direction of sounds suddenly changes in relation to my own head (which is outside of the game's world) it'll only lessen the immersion, not enhance it. As for movies, yeah, still not seeing the benefits, there's still one screen in front of you and the sounds are still related to what you see.