Sure its teaching something.
Actually it is not even doing that. You cannot "teach" aggression in this manner. In fact, in training IGP you don't teach aggression. Aggression is either in the genetic make up of the dog or it is not.
All this video shows is frustration barking, and not much barking. The dog makes no attempt to climb the leash at the handler and shows absolutely zero aggression. The dog DOES show frustration but not aggression.
You teach barking without aggression. In fact, the dog laying at my feet now was taught to bark and the reward was to bite a sleeve (much more advanced than the stage of this dog being tied back in the video). It could have been a ball.. or a rag (that is how puppies are started) and the game is "when you bark and look the decoy in the eye, you get the reward (sleeve or toy)." This dog would NEVER live bite.. that is a whole different kind of dog and I do not see this in this video. For this dog at my feet? it was a GAME.
Now what you CAN do (through very poor training tactics) is make the dog bite out of defense and threat (fight or flight response and you eliminate flight). This creates an unstable dog and no one wants that because that dog is a liability.
My current working dog is not aggressive. He does a beautiful job with the decoy but he would need to be taught a live bite. He is actually very friendly. I CAN "light him up" if being approached by someone that makes me uncomfortable but I am not sure he would bite them.. not at all. He really is more into being friendly.
Frustration barking as seen in the video does not "teach" aggression. It is, in fact, not teaching much. The ball reward is too infrequent. If he wants the dog to bark, he needs the ball toe be delivered as a reward for one bark.. then two.. and so forth building duration much the same as teaching a dog to sit and hold the sit.. start with 1 second and gradually build longer duration.
Another thing most do not know about barking is that it takes a LOT of energy. It takes a dog awhile to build barking endurance.