Always find your way back. Even without a signal on your iPhone. Mark your starting point automatically. Right direction and distance using compass. Find your route using your navigation app. Save your best experiences and locations. Add your own description to a location.
It is conceivable that you do not take extensive hiking equipment for a short walk. But in an unknown environment you can quickly get lost. A handy app like "Track Back" as a minimum equipment, could prevent a lot of suffering. Even without phone reception! When using this app, you also don't have to worry about an empty battery. When you use this app, you will be home long before your battery runs out.
The location data is only stored locally on the iPhone and no data is shared in any way