You don’t have to have navigation on the screen for “Full Self Driving” to work, so why can’t it just run in the background. I’ve often used BMW’s navigation system while having CarPlay active so the navigation directions would show up in the instrument cluster.
How would that work with EAP/FSD where the car is actually navigating for you? Carplay's Apple/Google/Waze maps are routing you one way, and Tesla's UI is not only routing you differently, but actually maneuvering the vehicle? The difference between your BMW experience and Tesla is, if you subscribe/pay for EAP/FSD, the car will actually be navigating for you, so it would not be a good user experience to have Tesla's maps in the background.
Now if you put your apple device in the background, then there is no need for Carplay, it can be handled via Bluetooth.
Carplay would be nice, but most people I know who own Tesla's seem to not miss it. I put my phone on my wireless charger, with Waze open, and I listen to notifications of redlight camera's, speed cameras, police, and hazards. I don't need it on my screen where I have my FSD Beta interface (showing the road, vehicles around me) and Maps on the other 2/3rds of the screen. I also have my SiriusXM streaming via my phone (I do wish it was built into the car like S/X has/had, I would even pay to have a module added).
I can see Carplay being less intrusive on a S/X with a cluster above the steering wheel, but in the 3/Y with a single screen, it would get in the way of the 15" screen that I currently use the full screen for vital info.