In the words of the developers themselves it is for, "Making money by feeding the Google Monster exactly what it wants whilst you barely lift a finger".
A cool, if overlong tag line, but it's not about that, it's about whether or not it's worth the money!
For the initial setup they recommend you purchase MANY domains, hosting and Niche Devil, you then install the Niche Devil onto your hosting account, then you run the script and insert your chosen keywords and affiliate links for the store you want to build and abracadabra, Niche Devil spits out a site with content and products in about 37 seconds. Got to be witchcraft, now all you need is a few spend-happy customers, and Niche Devil can even promise that with the aid of pinging, before you rush off and get your hands on this wonder, let's see what makes it tick.
The script that you upload to your server/hosting account via ftp will mean that it will have to meet certain minimum requirements.
If nothing else, it is a glorified niche store builder in the same vein as BANS stores, remember them? Niche Devil makes a lot of hype about it's "ever refreshing" content, pulling/scraping content from the Internet that relate to your chosen keywords, which works fine and looks pretty good but there may be issues over copyrighted material being used.
Niche Devil is promoting itself as with statements such as, "Hurry up, only available for 14 days" which can only raises various issues.
They have restricted the time it is available, why? Is it to make you purchase now or is it a case that they're worried about what happens when experience of the product kicks in and why sell a product that apparently makes money so easily and not use it themselves.