The Aqara Smart Video Doorbell G4 is equipped with a number of functions that distinguish it from a normal HomeKit camera, but also share some similar features.

### Motion detection and alarms
- The camera has a PIR motion detector that can detect movement in front of the door and send corresponding notifications, even if nobody rings the bell.
- This motion detection is not exclusively linked to the doorbell, but can trigger separate notifications and automations.

### Comparison with a normal HomeKit camera
- The Aqara Smart Video Doorbell G4 offers additional functions such as face recognition, two-way calling and integration with smart home systems (HomeKit, Alexa, Google Assistant), making it a more comprehensive solution than a normal HomeKit camera.
- However, it can replace many of the functions of a normal HomeKit camera, in particular by supporting HomeKit Secure Video, on-demand video and 24/7 recording (with appropriate power supply and storage).

### Summary
- The camera can trigger alarms when someone approaches the doorbell without the doorbell being pressed.
- It offers more comprehensive functions than a normal HomeKit camera and can replace it in many aspects, but it is specifically tailored to the needs of a video doorbell.