The two ideas are very different, but complementary.
Boxen is about getting your MacOS environment set up with tooling.
The author of the original blog posting is talking about how to automate the creation of a production-like environment in which to do your development.
The creation of that environment requires a few tools installed on your physical Mac, which could be managed via Boxen. For example, you might use Boxen to automate the installation/upgrade of Vagrant or your IDE of choice.
Boxen is about getting your MacOS environment set up with tooling.
The author of the original blog posting is talking about how to automate the creation of a production-like environment in which to do your development.
The creation of that environment requires a few tools installed on your physical Mac, which could be managed via Boxen. For example, you might use Boxen to automate the installation/upgrade of Vagrant or your IDE of choice.