By most standards, a 50mm lens would be classified as a "normal" lens, meaning that distances and spacial relationships would appear on the screen pretty close to how they would appear in real life. That being said, it's not intrinsically interesting just in the way that it projects 3D space. This might be useful in situations where you would want the viewer to be focused on dialouge or some other non-visual element, such as a shot/reverse shot conversation scene.
Also, the 50mm lens wouldn't have quite the field of view as a wider lens, essentially meaning that the lens can't "see" as much, and also has a shallower depth of feild, meaning that that there will be a smaller region of space that can be in focus at any given time.
Now, this might be what you're after, but in most cases, people find it more interesting to use wider lenses, where spacial distances will be exaggerated, or long lenses, where spacial planes will be compressed. In the end it really boils down to choices in style. In some cases, depending on the look and feel a particular film is supposed to have, a 50mm is a perfectly appropriate choice, but it seems that most people don't want their shots classified as "normal," and a 50mil lens is about as normal as they come.