In flight simulators or driving games, it gives more range of motion by tracking head position and gaze. The really good implementations allow you to do more he

In flight simulators or driving games, it gives more range of motion by tracking head position and gaze. The really good implementations allow you to do more head tracking, or more eye tracking, depending on your preference. FS2020 needed some tweaking in this department, when I turned my head to look behind me IRL, the game camera would spin like mad. The responsiveness is pretty shocking to say the least. In shooters, there's an added "snap to aim" feature that is borderline cheating, it snaps your aim to where you may be looking. I've only seen it in non-competitive and first person games though. For competitive shooters, the tracking can be very useful to know you weren't looking in the right place at the right time, if you care about that stuff. There is an overlay you can enable which shows where your gaze is calculated in real time. In third person games, gaze can be used to reveal information in the HUD (hide HUD elements unless I look at them) and to aim throwable objects. More gimmicky in these cases, but simply having more field of view without having to move your mouse/arm is useful IMO.