Power CMS USes server side php code. the server side PHP Code cannot be applied to static .html pages, it can only be applied to dynamic .php pages.
the underlying idea is similar to contribute, unlike contribute, it is an application that runs in the browser, not a desktop application. As such, there will be some things that can be done in contribute that cannot be done in Power CMS. For example, the client you create the power cms web site will not be able to create new physical pages in the site.
Power CMS Gives you, the developer the ability to create a page that can be used as a template for creating new virtual pages from. a template page creates a page with predetermined content areas on it. new pages can be created from the template that will have the same content area layout, but you will be able to add unique content to each page.
Simple is a relative term. On the power CMS Builder home page:
there is a feature tour video link. at the 0:20 mark and the 1:20 mark, there are screen shotts showing the client interface to give you an idae of what it will look like.
no, your clients will not need contribute to use Power CMS.
No, the client will not need dreamweaver or Power CMS. The site management interface is an Admin section to the Web site and is accessed through the Web Browser.