My last job had audits done on a semi-yearly basis and they always caught things our automated tests hadn't.
Broad stuff like providing controls for changing content (e.g. carousels) are what automated a11y tests fail on; other hard-to-test criteria includes WCAG 2.1ยง2.3.1 "Three Flashes or Below Threshold" and 1.4.9 forbidding "Images of Text"
Broad stuff like providing controls for changing content (e.g. carousels) are what automated a11y tests fail on; other hard-to-test criteria includes WCAG 2.1ยง2.3.1 "Three Flashes or Below Threshold" and 1.4.9 forbidding "Images of Text"