Is it even worth it? (General Question about ArchViz)

It’s a reality for about 4-5 years already. RTT use Nvidia’s Optix for their software, before that they had a custom solution. The reason why you don’t see something like Lumion running Optix is because whoever can use it, uses it themselves for end products, instead of building tool for competitors. Another issue is being locked into specific hardware and generally small market for this kind of products.