Aux cables were ubiquitous when cars were rolling speakers. I wouldn’t buy a car without an aux input, I didn’t care how many cds it could hold.

Now that cars are rolling screens, I wouldn’t buy a car without screen mirroring for the same reason.

No. No you can't. The specific example of preparing a playlist sure, but Carplay goes way beyond that. You can preload the navigation route, tweak it a bit, then when you sit down and plug your phone into the car its on the navigation screen. You can make phone calls using the microphones in the car. In a sufficiently integrated car you can have turn by turn directions pop up on the dashboard or a heads up display rather than having to look down into the center console while trying to work out which lane you should be in.