wireframe overlay was introduced during the development of skin modifier for better visualization of the topology during handling of the vertices, but this goes beyond by modeling I realized its potential when working with triangles and ngons, I can visualize how will be the geometri wen collapsing or welding edges, for this to work must have applied a subdivision modifier to the geometry.
test it and you will see how usefull is, here is some example and tut
An example of the visualization
