What can a PNA do better because it has information from flight instruments?

Flight instruments provide IAS which is used to take into account kinetic energy for final glide calculations. A moder glider at 200km/h has at least 100 meters of kinetic energy stored. Now pull up and you get an instant plus of 100 meters on your final glide. With IAS this can be compensated and the final glide reading will stay stable during the pull up.

Another advantage is wind calculation. Best reading for the headwind component ist IAS vs ground speed, especially on ridge or wave where no circles are flown. Also usefull on long final glides with no circles.

Best reading for the headwind component ist IAS vs ground speed, especially on ridge or wave where no circles are flown. Also usefull on long final glides with no circles.

That is actually mathematically incorrect. You can't determine the headwind component from just the ground track and the airspeed by simply taking the difference between both...

XCSoar however uses a more advanced algorithm that gets around that limitation if you connect it to a glide computer that sends TAS/IAS to the device. It is using a Kalman filter designed by John Wharington, that works pretty well and gives you accurate wind information within a short time of flying..