They're likely referring to "storing your config data in a repo" as "dotfiles" here. It makes sense in that light: where backing up your config data makes life

They're likely referring to "storing your config data in a repo" as "dotfiles" here. It makes sense in that light: where backing up your config data makes life easier for you when you set up a new machine, this makes it easier whenever you'd like to demo new software by creating a mini-VM. This is just expedited sandboxing with web access built in. The two feel complementary; you'd likely still want your dotfiles included in the images you're spinning up.