To some extent, I have to agree with TFA, though it's kind of clickbait, and doesn't have a lot of substance. I've found that I can much more rapidly prototype services or even test code with disparate tooling using containers over full VMs... I have an Ubuntu VM with samba setup, so I can use a gui editor (sublimetext) in my host, and run in my vm's shell via ssh.

I want to try out the new ASP.Net vNext, there's an image for that... io.js, there's an image for that... use the latest nginx with a half dozen plugins... yep. Hell, the easiest way to get the latest etcd running is via docker (golang has a really slick base image for projects btw).

Dockerfiles tend to work much faster than vagrant does in terms of launching a new VM vs building/starting a derivative container. Yes, you go through some discovery hoops, but no worse than any other virtualization.

I'm a pretty big fan all around.