Nuname hit the nail on the head with what we are after, an ID by which we could enter into countries without getting our passport stamped (ie Dubai), also something a "security troll" won't laugh at.
I have yet to see an aircrew ID card get someone through passport control. I have never achieved it and we travel pretty extensively.
An aircrew ID card is not a passport. Even when I have followed the airline crews through they have always been passport checked.
You maybe peeing in the wind on that one, especially if a private operator.