The only thing I really like about the auto-folding mirrors is that they are a visible indication that the car has locked itself. Because the only way I have of locking my new Model 3 is to walk away from it and let the car lock when it realizes I've moved away, which I don't entirely trust, or pull my phone out of my pocket, unlock it with my passcode since fingerprint ID is flaky, then scroll to the screen with the Tesla app, open the app, and press the Lock button.
With an old-fashioned fob, I'd pull it out and press one button. With the Prius I get out, close the door, and press the door button. But with the Model 3 I either have to take a couple of minutes futzing with my phone, or trust it to lock itself. Were it not for the folding mirrors, I'd always be worried the car was not locked.