It defines limitations and it creates flexibility.
We set boundaries by the breakdown. We define the limits of responsibility, how far an “accountable body” could go, to what extent he/she could be questioned, how their success would be measured and praised. This is what they get the “Great job!” for.
We add flexibility with the breakdown. We let everyone know their focus area. We define the area which every team could have their own style, execute the way they want, make a decision based on their discretion, we tell them this is where we “Trust You” with. (Please do your best!)
Breaking down is as important as integration.