Do not be sorry, please. I am happy enough that i could explain the point and it turned out to be not too crazy Just wanted to plant the seed.

User experience wise, CAN bus integration is kind of the only feature (besides a nice positioned screen) stock nav solutions have over mobile applications.
And it is heavily used as a selling point by car sales persons if you start talking against stock navs and their shortcomings regarding map updates and such.
So they are fully aware of the feature

This is a topic since 2006 for me when i bought my first garmin "nüvi" and was utterly disappointed that it strictly relied on gps, still costing 800bucks back then.
I did not even investigate into this before buying and was expecting it would be hooked into can bus as my former THB Bury Naviflash system from 2004 was. Thanks gamin and alikes for watering the term "car navigation" to brake into the market i guess.