CPU Raytrace versus PBR?

[PMMully]

I must say, the PBR stuff is pretty impressive. In this video below, if you look at about 10:47 into it, after the adjustments, the rendering looks pretty amazing, in 30 seconds with a medium card.

https://www.chiefarchitect.com/videos/watch/10251/real-time-ray-tracing-setup-optimization.html?playlist=139

 

I imagine mastering settings will take quite a bit of time, just like being a photographer, how you set the camera, lights, etc. Same with the standard, not as many settings, but it would be good to know if any of them relate to each other between rendering mechanisms? For example, setting sunlight options.

 

But my core question here is CPU Based RT on the icon on the top, versus PBR. When to use each, pros/cons? Would we ever go back to the CPU method? Or is it just there if you do not have PBR available via the card? If you look at this video, it seems to talk about standard RT, and the results are also impressive, but the results are different between X12 and X13.

https://www.youtube.com/watch?v=2VgAoVEJlSA