Power
You have the power to give someone the vacation of a lifetime. Travel agents have access to cheaper vacations, especially when it comes to cruises. Cruise lines court travel agents by offering them unpublished deals, credits, and cabin upgrades. In addition, travel agent customers are typically the first ones to get a hotel room or cruise cabin upgrade. Even your towel animals will be fancier.
Furthermore, travel agents gain access to privileged information by belonging to consortiums like Virtuoso or Ensemble Travel, which send agents exclusive travel deals. They're so exclusive we can't even tell you what the deals are, exactly. We imagine they're invitations to a week-long stay on the international space station, or something equally exotic.