Point taken if you use your pistol for more informal uses, as the huge majority admittedly do.
But everytime you remove that receiver from the grip frame you increase the tolerances between those two assemblies.
Again, this matters not at all to the huge majority of shooters.
But it did matter to the US Army Pistol Team back when they practiced with MkIIs and that is why they installed Dino's neat litttle gizmo.
Also, on MkIIs with serious target grips like these Nills-
-the backstrap area of the gun is covered by the grip.
Dino's gizmo serves well here too.
But like I said, you are completely correct in that this is a solution to a nonproblem for the great majority of MkII shooters.