Depends strongly on the practitioner and the methodology. It's one more tool at everyone's disposal; the more angles of attack amongst us all, the better. Trying too hard to standardize the approach has led to worse results imo: Exhibit A.

A shot-in-the-dark explanation for everything via the system itself would be that VI is largely a Te/Se endeavor, and the best fields to glue those disparate nodes together would be Fi and Ni. Gamma would be the home of VI at its most exalted. Fits well enough with what I've seen around here.

VI is just another thing I do that gets cross-referenced with a lot of other things I do.