How important are reddit-style flairs for people? There’s the raised issue https://github.com/LemmyNet/lemmy/issues/317 which has it listed as a far-future, with questions as far as how to handle federation.
Personally, having at least an initial implementation done on a community level would be largely sufficient, with expansion to instance-wide being optional. The situation I’ve found most useful, personally, is sports-related groups with your favored team being your flair. This gives context to comments without constantly having to say “as a X fan”
In certain communities they are pretty key. For example, I lurk a lot of trans meme subs on Reddit where user flairs are important for knowing the right pronouns to use for somebody and post flairs are important for content warnings.