Looked the card before I renewed my passport.  Didn't really seem like it was much use except as an ID.   A passport fits in my shirt pocket.  Then again when I fly I generally drag a briefcase as my carry-on, it has a lot of essential stuff in it...like my passport, wallet, kindle(books/music/videos), meds, money, backup of the home computer on a USB stick, and the other pocket stuff, baggie works well for a lot of this.  This way I don't spend a huge amount of time slapping my pockets at the security checkpoint.