From what I can tell both Puppet and Chef seem a little over-engineered, so I feel there's a niche for a simple (solo only) tool out there. By using something like Node it would be possible to a) run with a much smaller memory footprint b) have a more event driven architecture and c) run multiple downloads or other setup related tasks in parallel.
Additionally, javascript is NOT more widely accessible - if anything, learning non-DOM-manipulated javascript is INCREDIBLY painful for a beginner.
Remember, these tools are for system administration and configuration management, not for writing applications.
Your point about them being over engineered is much more interesting than you just thinking we need yet another system but in a different language. And javascript is certainly not the only way to achieve the goals you list. Just seems like an attempt to start a language war honestly.
I agree that JavaScript isn't the only way to achieve this. It's just that JavaScript is a language I like, so I thought I'd find out if there were others who shared my views. Perhaps I should have expanded more on things in my first comment. That being said, I'm pretty surprised by the negativity in the comments and downvoting.
That's a separate issue from what the system itself is written in...
The downvoting is probably over confusion, shared by myself, about what the language used to write the system itself has to do with the merits of the system.
(EDIT: perhaps having the ability to define recipes using a JSON only format would work as well)