They might serve as symbols of comfort. In many novels, emotional support animals can represent a character's source of solace in a difficult world, like a lonely person finding connection through their pet.
Often, emotional support animals in New York Times novels are a means of exploring human - animal relationships at a deeper level. They can be a mirror to the human characters, reflecting their emotions and states of mind. For instance, a skittish emotional support animal might indicate that the owner is also in an uneasy mental state. And these animals can also be a way to introduce themes of vulnerability and healing, as the characters may heal from their traumas through the bond with their support animals.
Well, in some New York Times novels, these animals can be used to drive the plot. For example, if a character has to take care of an emotional support animal, it can create various situations. Maybe they have to fight for the right to keep it in a certain place, which then leads to conflicts and developments in the story. Also, the relationship between the character and the animal can show the character's softer side or their capacity for love and responsibility.