This is just the first step. See here for the full process: https://github.com/docker-library/faq#an-images-source-chang...
All dependent (official) images need to go through the same process, so that makes it fairly problematic, and I think Docker needs to take a look at it for the future.
Ah, indeed... I thought the GA push was the final step but there's another manual process between that and updating the Docker Hub image tags: https://github.com/docker-library/official-images/pull/22541
It should definitely have a 'high impact' workflow that bypasses some of those manual steps.