Re: What did you get from the challange?
As far as I can think of, there exist only two vanquish tasks in the game which must be completed against human players - The Smarter than a Computer and the Triple Vanguish Streak multiplayer quests. There are also a few trophy achievements that must be done against a human player. Never once has community challenge required playing with other people. Even the revive challenge could be done in private multiplayer against AIs.