yea, those are cool, my freind has one of those, it plugs directly into the usb port, or you can use an adapter that clips over the front of it to help with misinsertion
That is small! I Think you should tell us what coin it is next to it though.
The British army experimented with a bluetooh dongle that was exceptionally small as a addition to dogtag's to carry a more detailed medical history and to aid in battlefield recovery but it was not adopted as it was to problematic in a combat situation and there was other downsides to it.