Sounds great.
It's a HTML/JS/CSS prototyping tool, so if you're building a web application for iPhone it makes it so much easier to get a basic prototype together and start hallway testing. Interface builder is _not_ the tool for doing this.
Additionally, just because you're not 'creating stuff like this in graphics' doesn't mean that you'll never create a proper interface for the application, it just means you can get a __prototype__ together quickly. Spending time creating a well designed interface takes away from what a prototype should be.
'...this screen looks like.. well you know a stock tableview'
And sometimes these people aren't in the same room/building/country
Simply dismissing the tool because you cant think of a use-case is a bit short sighted.
PS: also when designing for the iphone, elements have a surprisingly different feel when shown on a device.
Users can't interact with paper mock ups.
You have to re-draw the menu on every page you mock up or tell the people you're showing the mock up to imagine it. Both of these suck.
The Ratchet website talks about "iPhone apps" in general (not just web applications). And for non-web apps, storyboarding (in Interface Builder) is a great prototyping tool. And it has the advantage that it has all the common iOS UI concepts (and only them) and can be fleshed out into the real app afterwards.
As is the case with just about every other application, project, framework, and sexual intercourse: there are many ways to do the same thing and not all of them work for everyone.
See, the need this fills (and apparently does a good job at) is to give front-end web devs resources to write UIs in PhoneGap that look just like Interface Builder apps. Why would you want to do this? Possibly because you don't have iOS coders. Or perhaps your coders are already familiar with the web, so why not re-use their skillz?
The assumption here is that a front-end web dev can get a native-looking iOS app together faster in PhoneGap than a native developer can get a real iOS app together. While that's not always going to be true, it is probably usually true. And for some apps (like, virtually anything that's just business-oriented and doesn't require crazy stuff), the difference will not be noticeable by end-users (although it might trigger an uncanny valley feeling).