These two poems deal with a similar subject matter, which is the idea of death and the afterlife. However, they both approach the subject from a slightly different perspective. In the case of Whitman, he refers to death simply as a return to earth. For him, death holds spiritual meaning due to the connection of humans to the environment. On the other hand, Dickinson talks about an "afterlife" more concretely, as she thinks of it as a spiritual rebirth.
I think it is because personification is the attribution of a personal nature or human characteristics to something nonhuman, or the representation of an abstract quality in human form.
