@Sebastien, lets see what they say:

https://core.trac.wordpress.org/ticket/18493#comment:33

Technically, I think you have a great idea and it would be wonderful to have better control of the emails sent from your site.

BuddyPress is a particular use case, as you are sending email to your members who have signed up, so adding these features there may have been more compelling. Also, as the article says, Paul Gibbs had experience trying to implement something similar.