This is a sensible decision.

I work with Ruby daily, so using RubyGems to install a package is easy for me. On the other hand, when I find the installation instructions for a tool written in Python, I'm often confused: there will be a couple of options for installation, and I don't even know whether I've got pip or easy-install, let alone which of them I should choose!

There are downsides, however: the author now has to take on responsibility for building packages for multiple platforms and architectures.