The main promise is isolation: a Docker container that works on an x86_64 Linux machine will work on any x86_64 Linux machine in the same way. Want to quickly set up PostgreSQL for testing? Just run docker run --name postgres -e POSTGRES_PASSWORD=postgres -p 5432:5432 -d --restart=unless-stopped postgres and wait a few seconds. Docker is great for deployment as well as production deployments, and it even supports Windows Server containers these days.
According to Greg Marsden of Oracle, who also sits on the OpenELA board, the tool primarily helps achieve one of OpenELA's original goals. 'Although we all strive to ensure our Enterprise Linux systems are compatible, ELValidated lets us really prove that, to ourselves, as we build the platforms, and to our users, where the compatibility matters most.'