I'm already paying for a mobile phone; I'm happy to use CarPlay / Android Auto (where it projects a screen like VNC). I don't want a separate connection in the car that I'll need to pay for. I don't really need a data connection in the car directly while I drive.
Anecdote: I have a newer ICE car (okay not so new anymore), and its entertainment system rebooted while I was driving at speed at one point. It was fine because that's unrelated to driving functions. I would not be happy if that included my speedometer (which was an old school dial in that vehicle).