To build on that, it won’t even make things look better in all circumstances. When I was testing UE5.1 with thin, mostly occluded emissives, I noted that reference mode made the scene look notably worse. If you’re dealing with smoothly transitioning indirect lighting, it gives more accurate results, but it can compromise emissive scenes quickly.
For context, a default screen probe will trace 64 rays (last time I checked the presentation at least). 1024 is 16x that ray count, and it will kill performance in anything but trivial scenes. It’s meant as, well, reference, not gameplay tech.