I think the real purpose is actually to keep kids away and such. Ya know, when you have guests over and the little tykes are running loose, you don't want them to like mess up your "precious"..
It's just annoying how TT says they are "keys" but don't really make them keys. It's like they give everyone a "master key"..

.. They should've just made it some kind of child proof lock and be done with it.
Of course, that would've probably gotten a lot of complaints from various "new computers users", saying it is frikkin difficult to get the case opened...