[Ao7bei3s]

I don't think that's the most important part. Rather:

Full disclosure can also protect previously unaffected / potential future customers, by warning them of companies that have been so lax with their security that they've been breached.

So to achieve a comparable upside to full disclosure, HIBP needs to also make aggregate data publicly available. Which they do:

https://haveibeenpwned.com/PwnedWebsites