[dmartinez]

A mental analogy that I personally use for this is cabinets. A section of an app is kind of like a cabinet in a kitchen. Some people like opaque cabinet doors while others prefer glass. Other people go even further, and eschew cabinets for open shelves.

These differences in object and system visibility sometimes reflect specific use cases (e.g., a professional kitchen can operate faster with open shelving than with opaque cabinet doors). Other times, they simply reflect the personal preferences of the designer.