Use cases
The common shape is the same every time: a document exists, it is finished, and it has to reach somebody who should not have to download anything or make an account to read it. Email attachments get stripped, shared drives ask the reader to log in, and a PDF loses whatever was interactive about the original.
A link solves it, provided the link can be locked down as tightly as the contents deserve. That is the part these pages are about — not just publishing, but deciding who can open the thing and hearing back from them once they have.
Publishing something that should never be public? The mechanics of the gate itself, and why it is enforced before any page bytes are sent, are on password-protected static site hosting. If the document is one an assistant just wrote for you, letting the agent publish it skips the download-and-re-upload round trip entirely.
The page is served as you built it rather than converted into a preview of it. Charts stay interactive, fonts stay yours, and a layout that worked locally works on the link.
A reader clicks the passage they mean and leaves a note anchored to it, so you get "this number" rather than "the number in the third section, or maybe the fourth".
Re-upload to publish a revision. Anyone holding the link sees the current version, which is the difference between sending a document and sharing a page.