I’m trying to understand from the video why this is better, it looks like a normal high resolution textures with precooked shadow maps.

It has no dynamic lighting or effects, which makes the video look like a high quality game from 2006.

dynamic objects are still largely unsolved problem, I just tried to approach it in this demo. also this particular place doesn't have reflective surfaces, but technology supports it - check for example this splat https://superspl.at/scene/ff1d0393 or this one https://superspl.at/scene/6c822f84