“Noble silence”, or “functional speech” creates a standard to live up to. It is about control. You may go to a retreat and never get a chance to relate to others who are practicing. We are quiet when we sit down, hold still and look. When we get up off of the cushion, it is important for sangha to talk to each other.

https://www.youtube.com/watch?v=seeM5uCYJQw