besides photographic situations:
a 50mm prime lens is also cheap to produce. a new 50mm prime lens from nikon, canon, et al would be the cheapest lens you can get new from the manufacturer, AFAIK.
yet the same cheap lens is of a superior standard and quality.
a 50mm prime lens would usually also have a large aperture eg less than f2 - f1.9, 1.8, etc. you get a brighter viewfinder image and you can tackle dimmer lighting conditions.
as a beginner, i started off with a 50mm prime lens and stuck with it for about a year before getting a 24mm prime lens. the time when i bought the 24mm was when i felt the need to shoot wide, especially in enclosed and tight space.
otherwise, a 50mm lens is as perfectly adequate as other lens, in my opinion.