Many of the crew are working to support their families, so they send their pay checks home. While crews on industrial ships have arrangements so their families are paid directly, most passenger ships are different. Especially for Southeast Asia and India, where mail sometimes gets lost. You don't want to send a month's pay that way. To call their families, they buy calling cards.
Some cards are better than others for reaching particular countries.
I want reliability, to be sure these guys can get through. A cook from the Philippines asks how best to call home. Cushing recommends a card that, for five dollars, will give the man 22 minutes to speak with his loved ones. The sailor buys the card, then leaves. A Jamaican woman takes his place.