If you've been on the internet before, you've seen a section heading. If you have a page of text that is organized into different sections, descriptive headings will help provide organizational clarity for everyone who visits your site.
In addition to being an intuitive way to organize your site, the use of section headings also has a number of specific benefits for users experiencing certain limitations or disabilities. WCAG recommends utilizing section headings for the following reasons:
This rule has been designated AAA because it may not always be possible to implement it. Say, for instance, you've included a chapter from an old book on your site. The book's author obviously didn't write it with the Internet in mind, since the Internet hadn't been invented at the time, so while the chapter is organized into different sections, those sections are not titled. Adding section headings to this page of text, in this case, would violate the integrity of the work you're reproducing.
For more information on WCAG conformance levels, check out our post on <conformance>.