Docker is currently using the following sentence on their website to describe why
you would want to use it:
Docker provides an integrated technology suite that enables development and
IT operations teams to build, ship, and run distributed applications anywhere.
As simple as Docker's description sounds, it's been the ultimate goal for most
development and IT operations teams for several years to have a tool, which can
ensure that an application can consistently work across all stages of an application
lifecycle, from development all the way through to production.
You will learn how to install Docker on your Operating System of choice. You will
see that once Docker is installed, no matter which operating system you are using,
you will get the same results when running containers.