[DTV]

At the more extreme level you can have an entire set where the walls and floor are LED displays, allowing you to have an entirely virtual set (with what's on the wall shifting perspective as the cameras move). It's similar to a green-screen studio except the talent can see the set around them, and people blend in to the set much more convincingly. You also don't have to worry about problems with keying, and those on set don't have to worry about not wearing the same colour as the backdrop. You also get genuine reflections on elements like glass and the floor without having to fudge it like broadcasters currently do in virtual sets with chromakeying.

People on here keep evangelising this kind of 360 LED wall stuff and, while I think it would work as a part of a physical set - i.e., as a backdrop videowall that moves with the camera, I just do not see any real point to the every wall (and floor) stuff. Once all things are considered, it just isn't really that much (if at all) better than VR. Sure it does to some extent 'physicalise' the virtual set for those in it and does get rid of keying issues, but the virtual elements aren't actually inherently any better quality (if using the same renderer) and it is more expensive to install and less energy efficient to run. Plus, while those in studio can now see the 'set', it will always be from an odd perspective and watching it switch perspective with the camera must be distracting - and that's without getting into the calibration issues associated with camera switching.

The 'genuine reflections' point is also particularly interesting. You're right that you can have more reflective elements as part of the physical set, but the way that those physical reflective elements interact with the virtual set will often be less realistic. If you have a black glass desk top, as per ITV, and you want it to reflect a skyline as it would reflect a genuine one out a window, you can't achieve that effect using an LED wall as the physical desk can only reflect what is shown on the screen. In a VR environment, you combine the reflective technique that Stuart mentions above with a virtual skyline cyc and get a fairly real reflection.

I've attempted to demonstrate this difference by recycling my WIP VR Breakfast mock from TVLF...

The 'LED display' is on the left, the VR cyc on the right and shows the sky as a genuine reflection would, were the environment real.