Can I use it to watch while my camera man shoots video?

You can use an external device as a monitor when shooting video. This means with a smartphone, tablet or computer you can watch what is being recorded as the video is being shot. Since the video is being sent over a WiFi connection, the video display will lag behind the real-time video. This isn’t normally an issue if the camera is stationary, but if there is a lot of camera movement or panning, the lag may be inconvenient.