[lcrs]

Raytracing may be conceptually the most natural but it's not always the best choice for a lot of these cases - displacement, motion blur, depth of field and anti-aliasing are still often handled much more quickly by micropolygon/scanline rendering even if the lighting and shading is raytraced. Hair and fur is pretty problematic with raytracing too.

That said, physically-based shading is massively easier to art-direct, even if the "front end" as it were of the renderer isn't naively tracing rays from the camera. There's a killer set of slides and notes documenting ILM and Sony's switch to PBR here: http://renderwonk.com/publications/s2010-shading-course/