In addition to the sibling comment, you want to be able to check if the vehicle is charging and everything is fine remotely. EVs randomly stopping charging for various reasons is not rare at all. You want to get a notification.

You want to know when the vehicle finishes charging so you can vacate the public charger.

You want to be able to reduce the current when the charging is tripping breakers wherever you are.

On my EV that is very rare. Has never happened to me.

Controlling your charging. You shouldn’t be charging more than 80% for daily driving unless you want to destroy your battery.

You will almost assuredly also want to be able to precondition if you live in a cold climate.

Again, why do you consider those things as better done via a smartphone and an app, versus using the already built-in screen (the one behind the wheel)?

As I’ve already stated, I consider it better done by both. I don’t think forcing one or the other is a good user experience.

Every preview I’ve seen has stated that display is for the speedometer and backup camera, and that’s it. It’s not an input device.