I'm talking about the Passport Card ($65) versus the full Passport Book ($145):
https://travel.state.gov/content/tra...port/card.html
There are MSM news articles every month about how someone on a Caribbean cruise gets involuntarily disembarked from the ship at a foreign port, and learns that they can't fly home (or even to the ship's next port stop) with the Passport Card and not the full Passport Book.
With the chance that Coronavirus could leave someone behind in a foreign port, don't say that I didn't warn everyone to splurge for the Passport Book even if the cruise line says you don't need it for ship travel.....