I have always thought that it was one of the dumbest things I had heard on the radio.
I am of the mind that students should be taught to listen to the radio to gain situational awareness. If someone is calling inbound to the airport and you are near or have a potential conflict with then by all means speak up and let them you are there and what you are doing.
To me it is implied that when the initial position report is made, anyone in the pattern or in the vicinity should speak up.
Something else that I find irritating is annoucing everthing while in the pattern. Please, just downwind and final.
There is way to much jabbering on the radio.