Such cards are popular back in the pre-2000 toys especially in Marvel figures. We still do see some toys carry such gimmicks to lure collectors.
Today, I found a stash of Spawn bio cards which I cut out many years back since I cannot keep the cards that came along. Amongst them, I also found some old phone cards (which are used here back in the 90's for public phones), that have some cartoons characters on them.
Sometimes, it is some corners of hidden treasures that triggers some fond memories of our hunt.