You're correct in what you say, Dozy. The main point of having the CB identified in a particular way (we had a coloured collar on it) was so that you could eliminate the distraction of the clacker going off when it was caused by something other than a genuine overspeed e.g. a blocked pitot during the climb. The noise is more than a tad annoying and doesn't allow for effective communication when trying to carry out the unreliable airspeed actions and hear what your mate is trying to tell you about pitch and power numbers from the QRH. Pulling the CB and getting rid of that awful noise genuinely gives you a LOT more capacity to get the job done.
Of course, the CB should not be pulled for a genuine overspeed but quietened by slowing the beast down.