Sorry for the delay, folks. For my own purposes, I've concluded I prefer the greater control in post. Anyway....
1. A discussion about software vs hardware BW conversion does not make sense. All hardware solutions are in fact software based this way or another and all software is run on hardware. I used to design both.
Hardware = monochrome sensor = sensor without a colored array (Bayer, X-Trans etc)
Software = starting with a color image, and using tools in post to convert to B&W (LR, Silver Efex etc)
That should've been obvious from the post, where I was comparing sensor conversions and the Leica Monochrom to LR
2. RGB conversion has its advantages - flexibility in manipulation and many other ones. On the other hand Leica Monochrome gives such a beautiful rendering of details, especially in dark areas plus wonderful tonality incomparably better than my EOS 6D after any type of BW conversion I have tried.
Yes, I'm asking if the overall image quality of a monochrome sensor is superior enough to offset the loss of control in post.
I suppose I should have requested some side-by-side examples.