I am using certain badges based on group membership in order to allow users to choose a title reflecting their membership in a group. (Technically, what happens is that when users join a group, within 24 hours they are awarded a badge which is set to “Allow badge to be used as a title”.)
This is a nice way of circumventing the limitations of just setting the title via “Default title for all users in this group” in group settings as well as the uncertainties of setting titles via primary groups.
But: I’d rather not have users notified when they are awarded their group membership badge because it looks stupid and it’s bad education about what badges are for (achievements). What counts are the titles that users can choose from in their preferences. Hence my suggestion to add a badge setting Do not notify user when badge is awarded (or withdrawn).