да просто потому что "дребезг" у них ассоциирован только с звуковым (слышимым) эффектом.
словарь технических терминов обьясняет это так
debouncing A technique to avoid each reverberation of a closing switch or other electrical contact being registered as a separate event. After the detection of the initial closure, a short pause is made in order to allow the reverberations of the contact, known as contact bounce, to die away. The contact is then sampled again to determine its final state. Debouncing is often used in connection with the reading of keyboards.
