Parfait is for web designers and developers, or people who do both, and currently have a PSD comp to code workflow. If you receive PSD comps, and are asked to turn those into working code (web site, mobile app, etc), then we're building Parfait for you.
Parfait helps, by allowing you to do in the browser, what you might be used to doing in Photoshop, with a more streamlined user interface which is tailored for this specific purpose. It helps you get color, gradient, and font information, measure between elements, copy text and CSS, and extract optimized production ready images.
I hope this helps clarify the purpose. Let us know if this sounds useful to you, and if not, please tell us why.