I started early, in my lv2-3 to hunt or to give my players special abilities and usually my team is like this
Click image for larger version.  Name: TEAM D11.jpg  Views: 27  Size: 71.4 KB  ID: 50632

Did I notice my team playing a lot better with those sa ?
I 'm not sure. Then why I did that ? Because I could and I like that. It's a fun part of the game.
As like friends supporting/ball possession. I don't know if and how affects the match process but it's nice and surely affects the psychology of the opponent.
But if I "had" to declare, I would say it's like Emperor's new clothes