Thanks to @jtbayly for suggesting I post this in the feature category.
overview
A user is granted a new badge, this event triggers the user to be added to/removed from a group.
use cases
You have a hidden category with bonus content that you want users to be able to “unlock” like easter eggs.
You have a “Getting Started” category that is only viewable by users in the “Beginners” group. After being granted the “Certified” badge, a user is automatically removed from the “Beginners” group and this category no longer shows up.
If you can imagine other use cases, please add them below as replies!
Wow, yikes. Sorry for the double post. I did search around before posting but I definitely missed this. Happy to remove it.
Perhaps one nuanced difference is that I’d also like to see this work for a badge that is granted manually, say by a moderator, instead of automatically via badge queries. For example, we have a “feedback” badge that moderators can give out for really thoughtful posts; I’d love for this badge to “unlock” a flair badge (by adding them to a group). It seems like your approach (adding a mirror group) would cover this case as well. Though, the post focuses mostly on SQL triggered badges, so I thought it was worth mentioning.