No no, the idea is to use the GBuffer to select the pixels to trace, trace GI for only that pixels, and then reconstruct the sparse GI image.
I mentioned the GBuffer cause I need some info on the scene to select what pixels to kill, based on normals, albedo, stuff like that. The nice thing is that I have more info on the scene by using the GBuffer compared to the images I showed earlier, so I can make better guesses on what to keep and what to kill.
The core idea is to trace rays for less pixels.