Haven't analysed his performance deeply, but from whatever have I watched I feel he is able to challenge dynamics because the contestants didn't actually see him as a contender. His stance since the starting has been that he is there to "support" jasmin. People felt his efforts would be limited to a showmance angle with jasmin( who already is not really a threat to anyone).
Jasmine's enemies( Nikki and jaan or Eijaz or maybe even Rahul from the games perspective) didn't actually expect Aly to be strong willed or to play a game and never considered him a threat. Also, Jasmin's friends(Rubinav are decent people who already genuinely love her) are ready to support Aly the way they support Jasmin because they dont really expect him to create a rift between them( which Aly has been trying to do slyly since the starting).
I think he has been able to entertain us cause he cleverly took the reins of the house( and is not supporting jasmine , he is controlling her and others too) by acting as a wellwisher to a weak contestant. Also, I think bigg Boss has a big hand in this cause unlike jaan or Nishant who were exposed for their betrayal, I don't think Aly would ever be questioned cause he looks like a ploy of Bigg Boss itself.
Let's see how the contestants react to this as his personality unfolds in coming weeks.