@Mark_TI noted that general flight by goggles only sounds hazardous without a RC in the user's hands for obvious reasons like immediate course corrections or stopping flight.
You can't fly the Mavic without a controller, not sure where you are getting the thought that you could?
The only reason I left the controller turned off was to prove that your suggestion that the goggles might link through the controller was incorrect.
Now, to get back on point for this forum, with the Spark you will be able to fly without a controller if you want, but you can't use the goggles at all in that circumstance as the Spark requires the goggles to connect via USB to the controller.