Why does a ghost appear at the end of The Overcoat?

In Nikolay Gogol's short story The Overcoat, the ghost appears as a supernatural manifestation of justice for the protagonist, Akaky Akakiyevich Bashmachkin.

After Akaky dies from a cold contracted following the theft of his new overcoat and the subsequent refusal of a "Certain Important Personage" to assist him, rumors begin to circulate about a ghost haunting the city and stripping pedestrians of their coats. The apparition eventually confronts the official who had previously dismissed Akaky’s pleas. The ghost seizes the official by the collar and relieves him of his overcoat, an act that serves as a form of retribution for the official's callous indifference toward the humble clerk. Once the ghost has reclaimed a coat, he is satisfied and never returns.1