I think this is brilliant marketing on DJI's part. How are you going to find the Phantom users that need full groundstation? Offer them a limited (aka crippled) version on their phone for free.
So far I see the following:
1. Repetitive Flights - Let's say a farmer wants to check on his crops each day (you need full GS to be able to save missions).
At a press of the button, the job is done. or Local news stations who want an "eye in the sky" during rush hours. Monthly check on how your roof is doing, etc.
I am sure you might need an automated flight to check for drones coming even close to your property...
2. Flights where you lose control signal - It is very common to have trees and obstructions. You can set it so that it gets you where you want it to be, without having control along the way.
3. Automated drops to deliver that Amazon shipment ;-)
4. Search missions
At this point, it seems we have all the technology we need, except for collision avoidance. The rest is just software at this point.
We can automate the boring tasks, or fly under complete control to develop our skills and have fun.
There is a sinking feeling that you need to get used to, when you go beyond control signal and totally rely on this thing.
A tracking device sounds like a must have, with this application...