[Clarence]

Och på b_andersson:s url fanns rättningen till min gissning:

So why Google has created two navigation services: one full and one limited if both are for free? Because of licenses which G has signed with map providers - Google can't use map data for "real-time, turn-by-turn navigation", but they can for just "directions". This is why GD is available worldwide, but navi in supported places only.