Blender 2.8.1 has implemented this and the response has been overwhelmingly positive.
https://openimagedenoise.github.io/
It's the way of the future.
"At the heart of the Intel Open Image Denoise library is a deep-learning-based denoising filter, trained to handle a wide range of settings, from 1 sample per pixel (spp) to almost fully converged. Thus, it is suitable for both preview and final-frame rendering."
