Eren, as the bona fide title holder of Edinburgh, enjoyed a range of privileges and advantages.
This bestowed title signified Edinburgh's acknowledgment of Eren's actions, and it held weight in the eyes of the Anfang Alliance. With this recognition came access to classified information previously out of Eren's reach. Marla, having served as an ambassador for the Amazonians, believed it was appropriate to share certain insights with him since he was invited by the Matriarchs.
Eren's medallion prevented him from triggering the continent-encompassing array's suppressing effects, safeguarding him from any repercussions related to the privileged information he would be exposed to. As the highest-ranked medallion, it granted him the freedom to discuss and be knowledgeable about almost any subject of Anfang's past and present.