In the Dev Containers's document it said:

The Visual Studio Code Dev Containers extension lets you use a container as a full-featured development environment.

In my understanding, it creates a container that contains all required resources/library to develop an application locally. Isn't this the exact purpose of Docker and Docker Compose? Not to mention that Dev Container also requires Docker and dockerfile.

At the end of the day their purpose was to allow developers to instantly start a development environtment without worrying about dependencies. So what exactly is the difference between these two?