I think it merges raws by selecting the best pixel in the different photos.
Here, one photo is mostly selected except for one part of bright sky, so the noise is that of that photo so no noise gain.
Then I don’t understand the interest to generate 5 photos from the HDR photo with different exposure to blend them in enfuse. Again no noise gain as noise is exactly the same in the 5 photos.
Or is it a way to tonemap the HDR photo? is it better than tonemapers as fattal, Mantiuk…?