A procedures trainer is not a flight simulator, so this is being misunderstood by a lot of people.
Essentially, a procedures trainer is there for pilots to learn the "flows" for a given airplane/airline and how the various systems work without spending several thousand dollars an hour running a full motion sim, and since PC hardware has got better and cheaper over the last few years, those have gone from "wood mockup of flight deck with posters of the controls on them" to flat panel touchscreens and/or VR headsets.
The airline I fly for actually used the Majestic Q400 addon for P3D as a procedure trainer when we had a fleet of those.
If an aviation governing body signs off on MSFS for this, it's not saying "this is completely accurate", but it's more along the lines of "it's close enough to how the airplane works, and it's not gonna hurt anything to use it as part of training".