Way back, before we even had "the web", I used to teach an evening class on word-processing. My notes and examples all related to what people could use the software for - real-world examples, not what the software was technically capable of.

Then I changed jobs and started teaching and writing user guides for Microsoft Office. Again, it was all about showing how the software could do things to help the user.

Then I moved into public relations, and my releases and similar all took into account what the passenger/customer wanted to get out of things; which was not necessarily what the bosses wanted to say. My work would be customised for each audience.

In my experience it's not about documentation, but explanation.

developer.wordpress.org tries to be like www.php.net/manual, but doesn't have the wealth of user-generated real-world examples that the latter has. In this case, no documentation is better as there are people out there (yourself included) who do a better job of explaining how those functions can be used.