Running docker inside doesn't eliminate all the advantages. For example, you can test a full stack of components (frontend, database, memcache, background worke

Running docker inside doesn't eliminate all the advantages. For example, you can test a full stack of components (frontend, database, memcache, background workers...) on a single VM, instead of deploying 1 vm per component, which gets really heavy really fast. Another advantage is that docker on a vm is still docker: the container running on your local VM is 100% identical, bute-for-byte, to the container you will run on an octo-core box with half a tera of ram.