CCTV systems are very good at recording intrusion events, but they won't alert you to them as they're happening. Although some CCTV systems do have motion detection, these tend to have a high false alarm rate compared to a dedicated PID system such as a VibraSector. This is especially true for in adverse weather conditions. This means that operators can quickly lose confidence in alarms generated by motion detection CCTV systems.
The Detection Technology Blog