I think this is one of the first steps towards the gps course maker.
PD might be using this as a test bed for the gps software.
If a car driven around Fuji is collecting data saying the car is 30ft off its correct location, it will be much easier to tell with a set location, than trying to recreate a real Road, where if the data is off, you don't realise until you have uploaded all the data and processed it into a track.
PD might be using this to create 100's of virtual Fuji's, checking the data against the existing in game track, to iron out any programming issues.
I could be completely wrong, of course.
I own an OBDII bluetooth connector, that runs with an app on my phone as a data logger.
Only records G's, throttle position etc. Obviously not tyre temps etc.
If PD could find a way to have the gps app talk to one of these bluetooth OBDII accessories, that would be a viable way of many people using the feature at local tracks.
As far as I'm aware, gps technology is limited by the current satalites, rather than the hardware in your /my phone, so any gps data should be just as accurate from your phone, as it would be from a car with it built in.
Maybe