There may be a little confusion here. If you are in the GUI, a container is a JetStream object. So, you would only need to create a container if you were going to use the VDB.
If you are using the REST API or CLI, then there is a concept of Containers that relate to the database class of objects. When using the api/cli, you do indeed create a container when creating a VDB.
We are looking to clean up our terminology and nomenclature in a future release.