This option is intended for people who often overhear their bell. Switching a lamp via the plug can, for example, visually signal the doorbell in a noisy workshop or even for hearing-impaired people. The lighting up of the HUE lamps can also indicate to a teenager sitting in his room with loud music that someone is at the door. 

The siren can be plugged in, for example, where the mechanical bell is difficult to hear.