If you hide it, it will not re-install. However, Microsoft...have issued several editions of the same update and each one appears to WU as a new one. The old one (previous edition) does remain hidden, but the new edition of the same update will get installed.
WYSIWYG pretty much anytime an update is Revised and/or when an Optional updates becomes an Important (AKA Recommended) update.
- Important updates are not necessarily security-related.
And I think you'll find that the release of such a revised update will remove the previously-released version from the list of Hidden updates.
No updates will be installed without your explicit approval if Automatic Updates is set to the "Download updates but let me choose..." option. No updates will be downloaded without your explicit approval if Automatic Updates is set to the "Check for updates but let me choose..." option - but any approved updates will be installed without any further prompts. See:
• Change how Windows installs or notifies you about updates
NOTE: Any change you make now will NOT affect any updates already in the installation queue. As far as Automatic Updates is concerned, you've already approved those updates.
[I'll believe the "Automatic updates only" hype when I see it.]