The feature to use GPS coordinates inside geotagged photos as a waypoint to navigate to is an obvious one, but actually a pretty clever use if you think about it. Good job, TomTom.
Instead of writing down addresses when you visit somewhere new, just snap a photo of something at that location and you'll be able to get back there no problem. Need to direct someone to your house, or to a coffee shop? Snap a photo, email that to them and you're done.
Geocachers will be pretty thrilled at this too, having coordinates be integrated into photos of the thing you're looking for.