Really don't want to get involved in this again, but there is a huge difference between two exposures (say 1/50th and 1/200th of a sec at the same F-stop) and two different metadatasettings (say 200 and 800 iso on RED RAW).
The first example extends the DR by two stops, the second - on MX you don't even change the noise charracteristics and levels, you just change the visibility of it.
In other words: You basically change nothing but levels. And it has nothing to do with even easy HDR.
(On the M OTOH, there are good arguments to lower the ISO and pick up the image with a curve to avoid noise.
On the MX you don't even get that extra bonus by doing "ISO messing")
Back into my rabbithole again....