I only learned it randomly myself :- ). The Intel Denoiser was improved as well, it was originally just like nVidia OPTIX Denoiser, smudging textures too much, and also slow since it wasn't real-time like nVidia.
It's still not real-time, but the quality is now really good, exactly good enough from like 8perc. noise! For me it saves massive amount of time for previews.
There is apparently a newer version that could be integrated, so hopefully Corona team focuses on that, I don't think there is any point at keeping the HQ Denoiser. HQ Filter and DOF Solver are nice but for future, denoising will pretty much be necessary for 99perc. of scenes.
I have powerful workstations, Threadripper and Xeons, and render-farm, and my renders still take many hours and need denoising. Because there is always more technical quality to be done, more polygons, more resolution textures, more complicated shaders, etc.. the performance is not really growing that fast enough. So Denoising is pretty much the only future for off-line rendering (it's pretty much always done for real-time rendering which couldn't exist without it).
Perfect Denoising is the future of ray-tracing. There.
