SEO & Accessibility
Semantic structure, real headings, described images and keyboard paths, the things that help a screen reader and a crawler for identical reasons.
Why are these one service?
Because they are largely the same work. A correct heading order, meaningful link text, alt attributes that describe rather than stuff keywords, landmarks that say what a region is. A screen reader and a crawler both depend on those, and both fail on a page built out of unlabelled divs, which is what Google structured data is meant to prevent. Treating accessibility as a separate compliance exercise means doing the work twice and doing it worse.
What is actually checked?
Contrast ratios against WCAG 2.2 AA, focus visibility on every interactive element, keyboard traversal through the whole page, form labels bound to their inputs, and reduced-motion honoured. Then the crawl side: canonical handling, structured data, internal linking, and whether the important pages are more than three clicks from the homepage.
Where does structured data fit?
It is how a page explains itself to something that cannot read it the way a person does. Organisation, service, location, FAQ, article, whichever Schema.org type that matches what the page actually is. It is also increasingly what gets a business quoted in an AI answer rather than merely linked.