The early years of the Marvel Cinematic Universe introduced an important character in Phil Coulson. Through him, viewers could navigate the world of the MCU and its characters, with Coulson serving as the "average human." Once his character was killed in the movies, the other heroes were more than self-sustaining for fans, but there was a void that needed to be filled. This came in the character of Claire Temple, who acted as a Coulson of sorts for the street-level heroes of Marvel's Netflix shows.
Source:https://www.cbr.com/daredevil-canon-status-not-as-important-night-nurse/