That's a rather old statement. Nvidia and Apple GPUs have hardware-accelerated raytracing now. But even without specific raytracing features, lots of renderers use GPU compute for some of the raytracing workflow.
For instance, the Cycles [1] engine in Blender.
If you're into ray tracing as a hobby you have to play with it at least once! Cycles does probabilistic rendering and can handle tricky things like caustics.
[1] https://www.cycles-renderer.org/
[2] https://docs.blender.org/manual/en/latest/render/cycles/gpu_...
(edit) : TIL there's also Luxcorerender, which is also an engine that can render using GPU. https://luxcorerender.org/heterogeneous-computing/
I've merely quoted what the POX-Ray site has to say about it's own capabilities and beliefs at the time of writing.