The dogs that respond (run to you and expecting something good) to the tongue click are most likely trained with a clicker. Since the sound is quite similar so the dog thought you clicked and is expecting something good.
Obviously not all dogs are like this because dogs that are not trained with a clicker might come over to investigate what the sound is or just ignore it altogether.
Dogs don't naturally recognize the clicker sound, it's trained into them. If you raise a dog without using the clicker and start making tongue clicks, it might come over the first few times to investigate, but if no positive results, it won't come over every time. It might look at you since you made a loud noise.
Not all people know about the tongue click, I am not sure what you are using to quantify that.