Well, my use case is neighbour/friend websites (I'm not really a web person, but I "do computers", so I get asked a lot). Buying a $3/month domain with PHP webspace, slapping this and some HTML on it and basically being done is simple for me. I mean, compared to a "real" CMS... YMMV, of course.
Basically you just mark out some <div> tags as class="sc-content", and they'll become drag&drop WYSIWYG editable. The changes get written right back into the file, so you don't need anything other than PHP 5.4 and write permissions. You can even remove the SiteCake file again, and your site will just keep working (as static HTML).