Docker Hub may be thought of as a cloud registry that allows us to link code sources, generate images, and test them. We may also keep our pushed images locally or connect to the Docker Cloud to have them deployed to the host. We have a centralized container image discovery resource that we can utilize for team collaboration, workflow automation, and distribution, as well as change management by establishing a development pipeline.
Docker hub is a repository on cloud for all your docker images. (like github for code.) As docker helps you containerize your environment and build images, you can push the docker images to docker hub.
Apart from saving and shipping containers, It helps when you are creating an automated environment where changes made by a developer can be automatically built, tested and pushed.
You can build a new image or build image of a running container anytime and ship it. and can pull it the same way.