Because the full WCAG specification runs to dozens of success criteria with detailed technical language, teams often distill it into a shorter checklist covering the highest-impact, most frequently encountered items, such as alt text, color contrast, keyboard operability, and form labels, to make it usable in daily design and development work.
A checklist is a helpful starting discipline but is not a substitute for a real audit or genuine testing, since checklists tend to catch the same well-known issues repeatedly while missing edge cases, custom component behavior, and anything that requires real assistive technology or user testing to surface.