Quote - Excuse my ignorance, but what do you mean by "practical purposes".

By "practical purposes" I mean anything that is likely to be significant when you are composing a scene in Poser.

Quote - How would we actually apply this information in a practical sense?

I'm not saying that you necessarily would want to apply this information. My point was rather that focal length taken on it's own is not helpful, nor meaningful. Angle of view does at least tell you something real about the scene, focal length on its own does not.