Why don’t the dinosaurs in “Encounter Dinosaurs” respond to real-world light intensity?

I have a question about Apple’s preinstalled visionOS app “Encounter Dinosaurs.” In this app, the dinosaurs are displayed over the real-world background, but the PhysicallyBasedMaterial (PBM) in RealityKit doesn’t appear to respond to the actual brightness of the environment. Even when I change the lighting in the room, the dinosaurs’ brightness and shading remain almost the same.

If this behavior is intentional — for example, if the app disables real-world lighting influence or uses a fixed lighting setup — could someone explain how and why it’s implemented that way?

Why don’t the dinosaurs in “Encounter Dinosaurs” respond to real-world light intensity?
 
 
Q