This isn't really intended for people who want to make SuperAwesomeLinux 17, although it could certainly be used for that. It's target audience is software companies, and open source projects, who want to provide a quick and easy way to create virtual machines to run their software.
It's designed to get around the problem that to get your software into a company at the moment, you need to provide installation instructions, which may or may not work, and could take hours to follow. This is just what's needed to get anyone to *look at* your software. By providing virtual machines it becomes a lot simpler to get people to take a look at your software, because they just need to download it, and fire up VMWare or similar.
And then, when they want to put it into production, they can move the VM to their virtual servers (most large companies have them now, it's our standard method of deployment), and start it up.
That's me paraphrasing badly, if you want it from the horse's mouth, have a read of Nat Friedman's blog entry on the subject.