That’s not what we talking about. In Half Life Alyx this is the whole body that you move smoothly or by step, you head follow the move but still independent thanks to your headset. What you’re asking above was, if I understood well, the capacity to move smoothly the camera freely without moving your head, like what we have on monitor session. It could be by a stick, a joystick hat, or even trackIR. If you move the camera with your finger and not your head I assure you that you’ll be sick in seconds in VR. That’s a really different thing than Half Life Alyx and all other VR games. The pilot is seated, you’re seated in a plane.
Edit : check what happen in a nearly similar way when the Sim decide to move the camera in VR, that’s the same issue if you do it yourself for your eyes view (not the body itself):