For the health care camera case:
"The MV12W, with its fixed wide lens, is typically sufficient for providing an overall view of a typical patient room (15 x 15 feet). The MV12N may be considered when the desired field of view is smaller (for example, a hallway or a narrower room)."
I'll give a different viewpoint. I tend to tell clients to use the wide-view MV12 when installing on a wall (so there is a potential 180-degree view), and the narrow view MV12 when installing in a corner (where there is a potential 90 degree view).
Not much point using the wide view MV12 in a corner ...