The primary reason is to ensure reliable, uninterrupted security coverage for the home, even in the face of potential connectivity issues. If WiFi or Ethernet service is spotty or go down, especially during power outages or network disruptions, the home security Hub will automatically switches to a backup Cellular connection to ensure continues monitoring and responding, without any gaps in protection. Plus, burglars often try to disable security systems by cutting phone/internet lines - but a cellular connection thwarts this tactic. The hub also has an 8-hour battery backup, so it can keep functioning even when the power is out.