Tesla does not know how to do keys , they made the hole for a key ring too small on the Model S, so on Model X they got rid of it all together. As for functionality, I turned off my Model X's lock to close feature, since the lock button isn't recessed I've had the doors close on me a couple of times while getting out. I turned it off mostly in consideration of my passengers, I know to watch out, they may not. And the other day at a bank drive through I slid back in my seat after getting my money, and accidentally opened the passenger side falcon wing door. Now instead of making a better Key, they just eliminated it, I'm not impressed. I definitely like my i3's better, the handle is touch sensitive, touch the grid on the top to lock, and simply grab it to unlock. I don't have to get my phone out, and get into an app, or pull a card out of my wallet. Though you can use the app on the i3 if you choose to, I love honking the horn when I've spotted people looking at my car.
Disclaimer: this comment was meant as a review.