In common terms, a passport card is really just 'good I.D.' and unless you live near the Canadian or Mexican borders and cross them routinely it isn't really that useful on a routine basis. However, as I said it 'is' good ID and also a good choice for carrying ashore in the various ports in lieu of carting a book passport around. Thus I ordered the cards with my current passport renewal. When we go ashore on cruises we will carry our passport cards as photo ID. Less chance of losing a driver's license that way.