It seems to me that they are trying to prove that they are a serious 'AAA' engine, but these demos aren't that convincing to me - AAA is a lot more than putting fancy shaders on high-poly models, it's about handling huge amounts of objects in a dynamics situation, displaying large worlds via streaming, having a workflow that accommodates every creative professional, and offering great performance and visuals even on very complex scenes.
I've hear that even these highly impressive demos are fake - they built a ton of custom code for each one they rebuild core Unity features, meaning if you wanted to replicate this for yourself, you'd be in for a ton of development.
Comparatively UE5's Nanite demo showed off a tech that's ready to go for production.