An iPhone connected to a head unit running CarPlay and with Google Maps, Apple Maps, Waze, or another navigation app on the screen requires location services and GPS access.

Google Maps allows users to pin a favorite route to the Android home screen, thus starting the navigation to a pre-defined address instantly ...

Maybe your carrier has tight data caps. Or perhaps you'll be driving (or hiking) in an area with no coverage. Either way, you'll want maps and GPS that aren't dependent upon immediate Internet access.