General Hangers question

Hi guys, as I am planning on building my own studio I've been a quiet reader of these pages to learn about. First off, I bought the book "Build it like the Pros" and a lot of knowledge is in these pages. But some things I always see but don't understand are the hangers that will stay behind the wall. Wouldn't a tight insulation be much more efficient? Is there a special way they have to be placed? I also have seen studio buildings where there were hangers and then glasswool insulation before them?! Using the search function of the board brought me more than 400 hits and they weren't helpful for me to understand. Maybe someone finds the time to enlighten me with this...

Hi stolenchild, hope you make it home alright :) Try this search: resilient clips 66 specific matches !