In reverse order of importance:
1. Stunning capability. It is nothing to shoot on the shady side of the street with ISO 3200 and enjoy the luxury of f8 and
1/1000s. Doable with other cameras, but no other Leica when it was released.
2. The resolution allows very useable photographs from a fraction of the original frame.
3. The noiseless shadow detail can be pulled up from near black.
4. It only does black and white. You think like you've got Tri-X in the camera (or a mixture of Panatomic X and Tri-X).
5. The tonal gradation is so subtle. I took a photograph in Paris in late afternoon sun of two men talking at the entrance to
a bookshop. The recreation of the light of that moment is magical, never more evident than in an Epson 3880 print on
good Ilford paper.
Some shots hardly need any post processing at all. The flatness is evident in other shots, leaving you a flexible platform. I add no clarity or sharpening in Lightroom, ever. Mostly I am increasing contrast, moving the Black and Highlight sliders in opposite directions and raising the Shadow slider.
Did I find the original Monochrom worth it? Utterly.