The key is an actual (albeit stylized) miniature version of the Model S [1], you can see it right in the beginning of the video being handed over. Why did nobody think of this before. I just love the immediate connection one makes with this object. While the features it brings to the table (unlocking car doors on approach, loading personal settings, etc.) are nothing really new, there seems to be one missing: the only thing I don't see is a way to connect it to my keychain, but that would probably only destroy its beautiful finish.

So how is this kind of design strategy called, if there is a name for it at all? I am asking, because it strikes me as really obvious, while it seems like one does not see it too often.

[1] http://www.teslamotors.com/models/features#/styling (scroll down to about half of the page)