The Health tab is different from the SEO checklist covered in a separate post. Instead of an editorial checklist, it runs Google's own Lighthouse audit directly against your real, live, published URL — mobile and desktop separately — the same tool Google itself uses to judge page quality.
What comes back
Four real scores out of 100: SEO, Accessibility, Performance, and Best Practices, plus Core Web Vitals — the specific loading and stability metrics Google uses as ranking signals.
A page is flagged "Page Health: Good" once both SEO and Accessibility clear 80.
Why it matters
Instead of guessing whether your page is technically sound, you get the exact same verdict Google's own crawler would give — before you find out the hard way that it's hurting your ranking. Run it any time after publishing, and again after big content changes.