We are creating a website that displays geographic data on map (currently using Google Maps js API). We are currently using postgres + postGIS + php. It has been recommended that I look into usage of GeoDjango. I'm having trouble determining what additional geographic functionality GeoDjango provides above what is available already in postGIS (ie points, linestrings, polygons, distance calculations, area calculations, "within" logic etc).
Does GeoDjango provide additional functionality or is its intent to simplify the usage of existing geographic functionality?