NEO, I have a card and it works. I think it is novelty value. It is supposedly to give me priority, within medical need, and only in relation to my service related disabilities. When it worked for me was unrelated in A&E. The receptionist were busy nattering. Their conversation was more important; there was a 4 hour wait so I could waiting until they were ready.
I snappy the card on the counter; I was seen by a consultant within an hour☺