> It certainly gets hugely dramatic once you include shadows & reflections.

It's remarkable just how 'hacky' high-quality rasterised graphics is.

For shadows, render a scene from the PoV of every light source, create shadow maps, and then transform those shadow maps to camera space.

For reflections, use stencil buffers; for global illumination, use radiosity maps; for ambient occlusion, either bake it in or take a big runtime penalty and render them real-time...

Ray-tracing (and derivatives, like (bidirectional) path tracing, light transport, etc) should really be called simulations, and the physics and mathematics behind it is so straightforward, but extremely accurate. Even the simplest Whitted ray-tracers can produce fairly photorealistic rendering with simplified geometry, and extending ray-tracers to include very complex effects (subsurface scattering, PBR, even general relativistic ray-tracing) is comparatively straightforward.

The only problem is the absolute battering that ray-tracing does on traditional hardware.

Yes, that's true, there are a lot of things that are easier with ray-tracing; I'd add refractions, laser-sparkle interference patterns, and volumetric ray-marching to the list.

On the other hand, if you want to draw hidden lines (as for a mechanical drawing), draw lines at edges between facets (wireframishly) or to outline surface curvature, or add null halos around foreground elements, I think those are easier to do with a polygon or NURBS rasterizer.