I think it is a good feature that is forgotten about and not developed. It is a neat way to announce something trivial without disrupting the series, or when it is unrelated (e.g. "I am on an exam week, will be on hiatus").
Maybe they don't want authors to use it like it is a Facebook status (some do, and it's annoying though). It is not like the users are going to receive too many notifications because of it.
If you wanna make an announcement, it is better to do it as/in an episode. That way everyone will see it.