Those cards don't serve any legal purpose, I have something similar as well, and I've always been told I need the written doctors recommendation. I believe it is up to the co-op's discretion of whether or not to accept a laminated card from your doctor instead of the written recommendation, but the co-ops I've been to always want the written one and don't care much for the card I got from my doctor. It would be easier to just use a card, but I feel for legal reasons it's a good idea to always be carrying your written recommendation while you are carrying your medicine. Do most co-ops in your area normally accept the cards as a substitute?