The benchmark depicts a futuristic space scene (and not a Caribbean scene as the name would imply, with Port Royal being located in Jamaica)), with lots of mirror surfaces and extreme poly-count objects, and will be the first real time ray tracing benchmark offering shadows and reflections with detail not seen previously in benchmarks where traditional render methods are used.
Port Royal will require a graphics card with drivers that support DXR, which limits the market severely for early adopters. More graphics cards are expecting to get DXR support in 2019, so this will of course change.
With NVIDIA pushing ray tracing very hard and now UL/Futuremark giving it a push as well, ray tracing is unlikely to go the same route as HairWorks and will likely become mainstream sooner than people anticipate.
3DMark Port Royal will be available for purchase from January 2019. More details as well as a press release pricing will be available on 8 December.