Now that I've given it some further thought, having this particular tag canonical could be beneficial for readers in that it would allow for the readers to filter out those fics with the new tag filtering system. But I can't really come up with a 'positive' use for it - I don't think anyone would go specifically looking for fics that have been written while drunk, like they would with genres, kinks, tropes, or even most content warnings, because the tag says more about the author than about the actual fic.