There is a definite plus to docker compared to normal container/vm technology.What for? Clear container already use qemu, so why don't you use a simply VM instead?
Compared to normal package management, you can take a docker storage and move it to any server and install a new container and its up & running with the latest versions.
Reinstalling a server is just taking the container down pulling a new version in and starting back up.
This is not as easily done with a VM / container.