“Use proxy objects to organize complex inputs when making collections.”
I bypassed this pattern at first, as it is mechanically quite simple in Revit and Vasari to achieve, but there are some good reasons to get into when and why you might want to use it.
Individual loaded family instances can be pretty cumbersome to manage, and when flexing large models it can be time consuming with even moderately complex families if you have many instances. It can also help to simplify your larger assemblies of complex geometry for the purposes of diagraming, or export to external fabricators of consultants.
Revit and Vasari families, while potentially vessels for all sorts of information, can be useful by their absence of information. Sometimes you just want a family to give information about origin and direction, or be the outline of a space that you will think about later.
This example only shows placeholders for divided surfaces, but the same process can be used with any loaded family. This method can be used placing complex Adaptive Components, where a light weight skeleton is first used, or setting up incremented geometry like the ones shown here. You can see another example of this kind of lightweight placeholder and substitution method in this frantic video, where I use a line based 10 point adaptive component to lay out a large form before replacing the whole assembly with more complex solid geometry.