It's a formation that is very dependant on offensive formations
It's going 3 Safeties instead of 2 and a Nickel corner... So that big dime safety has to be able to cover slot WRs, be tough in run support, blitz off the edge , play a hook zone, and be fundamentally sound
Yea if you had charles woodson you would be golden but the majority of players can't handle the full duties off the role so it's relagated to a small part of the book.. it's not made for 70% of packages