It's a good historical anecdote about making progress in computer graphics, but ray tracing is largely an obsolete method, since 'path tracing', the method that stochastically solves the rendering equation by James Kajiya, can do global illumination way more realistically (in principle, it can give true realism). In fact ray tracing cannot do global illuminuation and any ray tracing engine that does that is essentially including a hack on top of its core ray tracer. You can even look at the images shared in the article and see for yourself as to how realistic or unrealistic they look.

Path tracing is not good for 'real-time' computer graphics at the moment, because GPUs need to be still more computationally powerful, though I think 2018 or 2019 is the year we'll have the first computer game based on path tracing. On the other hand, ray tracing is already easily doable in GPUs, since it's computationally less expensive than path tracing, but IMO, no one is interested in it since games either want maximum possible realism, or if they want "cartoonish graphics," they want a certain look, not the look imposed on them by the renderer, and ray tracing cannot give enough control to produce any look the artist has in mind (without massive hacks).

EDIT: I just realized, nVidia is promoting ray-tracing as the future of CG, and everything they're describing are actually qualities/features of path tracing and have nothing to do with ray tracing (except for this historical article). I'm seriously perplexed. Maybe nVidia's marking department thought the word 'ray tracing' is more catchy, and more people know about it, so they should use it everywhere. It's common knowledge in CG research community that ray tracing cannot do global illumination.

EDIT 2: Another possible reason is that if they start mentioning path tracing, people will start asking questions about the difference between ray tracing and path tracing, and sales people don't want to get into that. It's a bit like calling LCD displays thin CRTs out of fear that if they mention LCD, people would start asking about the difference between CRT and LCD.