Author here. This article shouldn't be about using Yeoman or not, and if that is what you are getting from the article, I might need to do a better job at writing. As I get further along in 'An Angular Workflow', it will be more about using angular than it is now.
The bootstrap project is a combination of tools, including some ideas taken directly from Yeoman itself. I have it there as a starting point so we can just get to coding.