Their reason for using Salt (from the Distutils mailing list [1]):

"> Can you say a little about the choice to use Salt instead of Chef? I don't really care either way, but am just curious. Is it because Salt is written in Python, or were there other reasons (functionality, etc)?

"I’d need to ask Ernest to be sure, but I believe it was mostly that he was more familiar with it. The fact that it was written in Python was a bonus as well ;) I don’t think that there was anything that Chef was missing or that Salt had over Chef, just familiarity of the person who did most of the work. I’ll double check with Ernest to make sure there wasn’t another reason :)"

[1] https://mail.python.org/pipermail/distutils-sig/2014-January...