They might have wanted to build the demo on some game that has more realistic geometry and textures to showcase the benefits of raytracing. Quake 2 still looks

They might have wanted to build the demo on some game that has more realistic geometry and textures to showcase the benefits of raytracing. Quake 2 still looks 90's mostly. I can spot the "hard" features in the demo myself to some extent but given well-known shading techniques you could get a close enough similar emulation of the effects that would fool most people.