Cleanup can be as simple as deleting the latest deployment directory, if the script gets that far. The article is about using built-in Linux tools for ‘easy’ application deployments. One can also use dedicated tools, as you suggested, to further automate the deployment process.
Author here. In case it’s not clear, this article isn’t about installing Linux packages; it’s about deploying multiple versions of software to development and production environments.
Seriously, why the negative tone? If I’ve offended you, I’m sorry. You might think that I’m wasting time, but there are multiple ways to skin a cat. I prefer not to use DEB packages for deployment, though others might.