I've owned 4 different cars with built-in Nav systems and have used a couple of different aftermarket units, plus using my phone, and I much prefer using the built-in Nav systems, despite their shortcomings. The main reason for this? Integration with the car. The system is always there and on an available. There's a dedicated input system that doesn't require fumbling with an external device. I generally have a larger display that is more ideally located. If I have audio prompts turned on it goes through the car's speakers automatically and I can easily control the volume. I don't have to worry about whether I have a working cellular connection or how much data I'm sucking down.
That said, I knew when I bought my Bolt it didn't have a built-in navigation system and instead I would have to use Carplay or Android Auto in order to get Navigation functions. I actually read the press releases, looked over the spec sheet, and even looked at the manual to know this. Wasn't too hard to find this info.
It's a less than ideal setup, but it works for the most part, when I remember to plug in my iPhone. That's the biggest pain for me: remembering to plug the phone in. I would love for a wireless version of Carplay, but wireless Carplay doesn't appear to be forthcoming anytime soon for the Bolt, or pretty much any other car that supports Carplay. The only car that supports wireless Carplay currently is the 2017 BMW 5 series.
The big advantage of using Carplay (or Android Auto) is that you kind of get the best of both worlds: you have a large central display to use, integration with the car (display, controls, audio), and you always have up to date maps, plus traffic info. The disadvantage is that you have to plug in each time, and you are forced to use data, and of course, have to use a compatible smart phone. Life is full of compromises, this is a rather minor one in the grand scheme of things.
If you are willing to buy an EV, which requires a different way of thinking about owning and driving a vehicle, then you are already working outside most people's comfort zones. It's not a huge leap to also try a different Navigation system at the same time.