Almost every server applications (databases, webservers, webapps) are available as docker images. It's very easy to deploy those apps using docker, which is why it's taking over sysadmin world by storm. Previously, handling a big web application deployment is a complex task that requires a dedicated team. Now, you can just package your app as a docker image, and other people that know docker will know how to deploy your app without having to know its internal dependency graph first.
Certainly not for production, but when you can't run x86-64 images, just simple prototyping or building images that requires x86-64 will require using external servers instead of using locally installed docker, which will be a huge barrier for casual prototyping.
It's not quite as simple as GP implies, but why not? I work at a place running Docker in prod, and our only issues are with the swarm networking, not Docker itself.
