Isn’t Musks whole idea that we set the sat nav to say where we’re going and all the indicating and directions will be done for us, not just the steering? You’d not need to touch the buttons yourself, in the same way we no longer generally touch headlights (full beam issues aside), the car knows what to do and does it.
It would be quite a step change (for me at least) to use Nav on every trip, I rarely use it on any trip to a place I’ve been before if it’s less than 50 miles, and that’s probably 95% of my journeys. Self driving will force that, the car can’t drive you anywhere unless you tell it where you want to go, but that’s a different topic.