The simple fact is that Apple Carplay is best for cars where the inbuilt Nav and other user interface is relatively poor (e.g. Kia/Hyundai, GM, Ford, etc) and people are not prepared to buy the inbuilt system. It’s all well and good giving Apple Carplay for free on these as it reflects well on the car manufacturer.
BMW and MB spend a lot of money on developing their system integration and it shows.
Try driving one of the “lesser marques” and see the poor graphics on their systems - then Apple CarPlay makes sense to me.
I also assume that using Apple Carplay uses the data on your phone?
I have no need for speed camera warnings (although I know that people use them as an excuse to be aware of accident black spots).