The Tesla vents are definitely a debatable choice. I like them, but I acknowledge they are mostly an aesthetic choice. Many Tesla removals (stalks, etc.) come with a cost savings, but I don't really see it with vents. You're probably adding parts in the form of little motors and wires to power them. But they do fit with the theme of autonomy. Software can remember their position for each driver, or could hypothetically cycle through different positions depending on mode selection. (They might do this already but I don't pay close enough attention.)

Edit: Now that I think of it, it's possibly still a huge cost savings in that you can have interchangeable parts across all models, since the vents are hidden to the user.