Useless birth certificate cards

Why is it that some states issue a wallet-sized birth certificate? They are not real birth certificates because they can't be used for things that you need birth certificates for, like getting a passport. It's like they've been punking all these people who have been born in their states. "Here's your birth certificate -- Psych! It's a birth card! Ha!" I mean, what is the point of these little fake doll-sized cards?