Purpose of this API is to provide data about cities and countries.
There are plenty existing APIs that are holding data about cities or countries.
This one may be unique in case of holding specifically historical data that may be used in researches.
It is a pet project to get more experience with Google Cloud Platform (especially, Cloud Functions, Cloud Endpoint, IAM etc).
Also I want to make my Google Cloud Project available in the future, so people can be invited to the project and see how it looks like from inside. I think that it may be quite helpful for those who are starting to work with GCP.
This project can be considered successful already as I proposed a small fix for Cloud Firestore examples project.