At the risk of stating the obvious to some of you, I thought I would make this point about flying a Phantom with the DJI Goggles.  None of this was clear to me when I first purchased the goggles.
For the Phantoms, the goggles connect to the controller via its USB port.  This is the same USB port you would typically plug in your phone/tablet to access the DJI GO app. So clearly you can't use both the phone and the goggles at the same time.

This means, if you use the goggles as the pilot, you will need a companion to keep the drone in view and you will rely entirely on the goggles for telemetary and intelligent flight modes.  Or your companion can wear the goggles and you (the pilot) will fly without telemetary,  using just the controller and line of sight.  You could of course unplug the goggles and plug your phone/tablet back in midflight - but the point being - you risk not be immediately aware of any warnings.

Another alternative is to plug the goggles into the (optional) HDMI port of the controller.  They will then act like any other HDMI goggles at this point - you will have telemetary - just no head tracking etc.

None of this applies to the Mavic and you can use both the goggles and a phone/tablet simultaneously.

Happy flying

I wasn't clear on that either. Personally I don't mind not having the app while friends and family are taking a ride in the sky with the goggles. I just wish I could keep them connected for more than 5 minutes. Seems like once they have the tiniest bit of trouble they freeze and disconnect never to return. I'm still trying to figure out why.