It's kind of funny how long I spent examining the packet looking for the card before I figured it out. I guess I have contradictory attitudes about it. I get annoyed that I still have to carry my United card, as lounge dragons abroad love to deny entry without the physical card. And yet, somehow it feels cheap that they didn't send me one. I kind of like having it just in case.
The only time I've found the physical card useful was when I was traveling with a friend who did not have status and the reservation was in his name. They were happy to recognize my status from the card and grant it to the reservation. It was in a foreign country where I don't necessarily expect to have data.