RIM’s smartcard reader has long been a great security tool to secure high profile BlackBerry devices. I have never actually seen one in use since it is mostly limited to government and security conscious jobs. Though the idea behind a card reader that disables a BlackBerry when it is not in range is pretty slick.
Its a form of multi-factor authentication that compliments passwords and may even serve to replace them though most government agencies still require a 6+ character password along with the card. You can read about it in the NIST security checklist for BlackBerry Enterprise Server.
The upcoming update to the Smartcard reader will be smaller and lighter along with supporting stronger PIN passwords. Check out the full details in the press release. Sadly there is no picture of this smaller version available yet.