So the idea of this pattern is to try to keep scss files exactly coupled to view files where the contained css is only consumed by that view.  Keeping stylesheet filenames mirrored exactly to view filenames helps keep the scope of any given css explicit.

Although scoping down to a page or action might seem like a simpler & easier way to do things, it does encourage a bit more use of helpers which should be avoided where possible.  Say you're styling a certain partial which appears in multiple actions.  If your scss files are scoped to actions, you can either duplicate the styling for this partial, or put the styling in a helper.  If scss files are scoped to view files, you can simply couple the styling with the partial file without introducing a helper.