Tesla is different from all the other carmakers, and part of that was pioneering this kind of advanced in-car tech before CarPlay even existed. It makes sense. And now we learn that Tesla is making their own phone, so this makes even more sense.
For the record, I hate both systems. It's no wonder Tesla drivers always act like they're distracted on the road, probably looking down at touchscreen climate controls. And I cannot believe CarPlay is an Apple product when it behaves in such unintuitive and broken ways; all that tech just to be actually worse than an aux input.