Many of us carry ID cards at work. In my industry, it's common to never take yours off all day, and it's so satisfying to wear it instead of a lanyard and plastic case.
Outside, I'm not going to be mistaken for a retail worker if I forget to take it off. A little dignity goes a long way, and the first thing that comes to mind when seeing this kind of keychain is "authority", not "geek crew".
I was able to order it with no problem, at a very reasonable price, and it arrived the next day, ready to show off at the next team meeting.
So whether you're walking around with a military CAC, corporate ID, or even just a photo ID or pass, you'll feel much more dignified than with a lanyard.