What? Automatically installing VirtualBox images, and setting them up with a development environment in 2-3 commands does seem "that different than just using VirtualBox directly"?
A shell script that can spin up VirtualBox images and run puppet to provision them isn't very difficult to make and would vastly outperform vagrant.
Vagrant isn't very good as a piece of software, it's very good as a standard, because it can be used as a standard description of a development environment.
