You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
Found some more information: Mr. Botts on Twitter
Supposedly it's related to whether the phone has NFC or not. Which is odd, because I don't think any of the app features actually use NFC at the moment.
EDIT: This Japanese tweet implies that the app tried to implement an NFC feature where you could unlock your car by tapping the phone to the B pillar: Gusfring on Twitter Not sure why this would be useful when it can unlock via bluetooth.