These are CIA officers, engaged in a major crime. They have non-official cover identities that are supposed to be used for operations. What possible reason would justify using your real identity when committing serious crimes rather than your agency provided non-official cover identity? Do you think the CIA doesn't know how to make decent cover identities by now? That they're so bad at it that United Airlines or Hilton Hotels will be able to see through them?

Following the lead of corporate America, the CIA has largely given up on having Americans do actual work. CIA agents are managers, and they source local people to do the dirty work. If there's one thing professional managers love more than meetings and power point, it's travel rewards points. As a fan of spy novels and movies, it's a bit sad to think about how in real life, national security could be compromised by an enemy agent offering platinum upgrades.