Mine was also at JFK; a few minutes of my (short) "interview" were used to give me Global Entry cards, which describe the program, with the intent of my giving them to friends and acquaintances to alert them of the features of the program. [I still have a few of these cards left.
]
Haha I got those too! The CBP officer who conducted my Nexus interview asked me if I have any acquaintances or relatives w/Nexus, to which I replied yes.
He then gave me these cards to give to people that "let them know Nexus is now GE eligible"