Not sure what you meant with _most folks_, but I'm under the impression that most people on mac, who use the Terminal on a daily basis, use homebrew as their package manager.
Actually, the target audience of Traveling Ruby is primarily users who use the terminal often. See https://news.ycombinator.com/item?id=8718614, where I explicitly mentioned Chef Solo and Heroku Toolbelt as two example use cases for Traveling Ruby.
You can still use Traveling Ruby as part of a toolkit for making an app that's targeted at non-terminal-using end users. For example, by making a GUI app that shells out to a CLI engine that's written in Ruby, powered by Traveling Ruby.
I don't think the target audience (end users) are people who use the Terminal on a daily basis.