If I am not mistaken , it means that on the models that support them, you can see the phone number and other info of the POI and can then through your bluetooth phone connection, dial the POI.
It just makes it simpler to contact the POI on the move...
I want to create my own or update an existing POI (not done one before) for ANZ banks & external ATMs (by state). I know extended poi's can have telephone no's but exactly how much info can you have in them (allowed fields?) and in what order?