There has been much debate in recent years about the relative merits of optical see-through XR (as in the Hololens or Magic Leap) versus video passthrough XR (as in the Vision Pro or Quest Pro). I have a very strong preference.
It comes down to the question of immersion. Do I feel that the XR objects that I am interacting with are immersed within my world?
In the case of optical see-through, objects are visually clipped to a somewhat small area in front of me. If I turn my head to the side by even a moderate amount, the object that I was just looking at will disappear.
That is not the case with video passthrough. A virtual object in video passthrough is visible throughout your entire field of view. However you turn your head, you can see that it is still there off to the side.
On a visceral level, these are a fundamentally different experiences. Objects in optical see-through feel transient and ephemeral. In contract, objects in video passthrough are persistent, the way real objects are — you get the feeling that they are still there even when you are not looking at them.
To me this makes all the difference.