I think it creates diversity in what tasks people have.
Also, let's say "A" was completed so that everyone but the Scapegoat got "A". Now, without random awards, nobody has incentive to help that one player satisfy "A" at a later time.
But that actually the way it would work in an actual breakout where no one else would have any incentive to help someoneelse get in on the plan. This mechanic just comfuses me.