I perused Ezio's website, and found three B&W monitors they currently sell, their "GX" series. Looking at the specs, the thing that stands out to me is that they're really bright: 1,200 cd/m^2 for the GX240 and GX340, and a whopping 2,500 cd/m^2 for the GX560 ! I bet these monitors are brighter than equivalently-backlit color displays from not having a Bayer filter in front.
Speculations on why medical monitors might be that bright: they can probably be better read in brightly-lit medical settings, shine through overlays and negatives placed over them, and be more easily read by some patients with poor vision.
They also offer palettized grayscale: up to 1,024 tones from a palette of 16,369. I'm not sure how useful that is in practice, but is is a unique feature.
https://www.eizo.com/products/radiforce/gx240/