#4 To actually further the Messiah gimmick
One thing that you must keep in mind is that Austin Theory has joined Seth Rollins' faction at a time when he is away from the title picture. Austin Theory has chosen to align with Seth Rollins at a time when he seems unhinged when he took out his frustrations on Rey Mysterio in a segment that had many people gasping with just how brutal it was.
Seth Rollins recruits Austin Theory
Bear in mind that Seth Rollins, who has been a top guy on RAW pretty much since the dissolution of The Shield is now out of the title picture. Austin Theory needed to enter his life in the manner that he did for him to further the idea that he is a messiah, that he picks up people and lifts them when they are down and out. In a way, there are several similarities with CM Punk and his Straight Edge Society gimmick as well.
And this is how he stays relevant and interesting even outside the title picture.