A Smoke Sensor is used to quickly detect and alert in case of fire or smoke. A single group address needs to be configured to indicate an alarm, while two optional group address can be specified to indicate that the device is faulty or the battery is low. You can receive notifications when the sensor detects smoke or fire and create automations based on these notifications in the Home app. It can automatically turn on all the lights for example.
Note: This sensor is not available in Alexa and Google.