They answer different questions, and the difference is not obvious from the words:
Publish copies what you edited in development over production, then renders the site.
Build renders production as it already is. Nothing moves.
Publish is the one to press after editing anything. Build is for when the content is already promoted
and only the code changed — a template fix, a new rendition ladder, a failed build to retry. Offering
only Publish would mean every retry of a build also re-copied a database and took another backup,
which is a lot of machinery for "try that again".
Build reads first and quieter, Publish last and solid: the row runs towards the action somebody
actually came for.
One busy state and one failure panel between them, because only one can be running.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>