Bastion, in Overwatch 1, used to make the Null Sector spawn noise when he used his ultimate, which would be heard by the player and by the enemy team.
Now when he uses his ultimate in game, it makes the standard Bastion ultimate exclamation like all his other skins. I believe this is a bug, and should be fixed.
One of my favorite appeals of the Null Sector skin was that it had a custom sound associated with it, and is a fine addition I think should be carried over to other skins in Overwatch to really make them pop.