You really need WiFi or the cam will need a screen, even with WiFi there's usually a few second delay as the signal is transmitted to the phone. Otherwise its nearly impossible to aim the camera appropriately for the vehicle and mount location you choose. When you do need the footage most, like on the side of the road waiting for the Police to right up an incident you're involved or witnessed you can preview the footage prior to offering (incase you're the reason) that you have a recording proving what happened.