I haven’t actually used a Tesla or Rivian system, but I’m happy to allow that they may do certain features better than Apple. The thing I really want CarPlay for, however, is what someone else mentioned: continuity. I like getting into my car and having the location for the appointment I’m heading to (from the event on my calendar) pop up on the screen so I can just tap it and go. I like being able to quickly navigate to my kids’ locations (from Find My) when I am headed to pick them up from somewhere. I like being able to use Siri to fire off a quick message to anyone. I like being able to hop among my family’s cars, or even rentals, and have my music continue right where I left off in the middle of a long playlist. I like having my car pop up the button to open my HomeKit-controlled garage door as I near the house and trigger other things to happen inside the house as part of HomeKit automations that know who I am. I like having things like favorite/recent/frequent locations and preferences (avoid toll roads and such) from my maps app work exactly the same and be consistently available, again, no matter which vehicle I’m in.
For me, it’s not about comparing specific map interfaces or whatever. The functionality I find important from CarPlay is similar to what I get from cloud services that integrate all of my devices. CarPlay ties my car, through my phone, into the rest of my life. Having to use the car system feels like going back to a single computer that could only connect to the Internet through dial-up and only synced with other devices by plugging them in and running some specialized software. And what little integration these systems have tends to come at the price of privacy. For example, I’m not crazy about the idea of sharing all of my destinations with a company to resell to others for advertising purposes, and I can’t tell you how many rental cars I’ve gotten into to find someone else’s list of contacts in there because they did the Bluetooth syncing so they could have a feature that CarPlay handles without that sync.
That said, I would prefer to stick to my phone for functionality in some cases where the car does offer it. For example, maybe I want to use my SiriusXM streaming subscription, or use the Target app to tell them I’m on my way to pick up an order. The car system might offer these apps as well, but just getting logged in is a pain because they don’t generally offer a good way to not have to type my 40 character long random password that my phone auto-fills from 1Password or Keychain. And when I do get in, I still have to set up preferences and such for each car. And sometimes, they don’t offer the app, or their version of the app isn’t as well-maintained as the one on my phone. It’s often easier for these things just to use the apps that are on the phone that you know get the most attention from the companies and which are already authenticated and set up how I like them.
And yes, there’s the pricing aspect of it as well. Different companies do different things, but it’s not unusual for car companies to try to get you to pay subscription fees–sometimes heavy subscription fees—for things that CarPlay gives you for free. Think, updated map data, access to real-time traffic data, or cell access.