One other hypothetical use of a 3D interface is as a way to conceptualize "true N-dimensional" data. A 3D experience indeed doesn't help any rational conceptualize of a rational situation but it might, maybe, allow you to mobilize the unconscious reflexes humans have for dealing with regular 3d space. But all this might also a 90s cyberpunk fantasy.
One other hypothetical use of a 3D interface is as a way to conceptualize "true N-dimensional" data. A 3D experience indeed doesn't help any rational conceptualize of a rational situation but it might, maybe, allow you to mobilize the unconscious reflexes humans have for dealing with regular 3d space. But all this might also a 90s cyberpunk fantasy.