Assigning commit's author by bitbucket username

There are methods to assign bitbucket user as author of a commit:

• Alias
• Adding e-mail, associated with bitbucket account, to commit meta-data via configuring local repo/.hg/hgrc or global $HOME/.hgrc like this:

#!ini

[ui]
username = John Doe <john-doe@examle.org>

Two questions:

1. Why either ssh-key or bitbucket http-authorization doesn't give immediate assignment of commit's author?
2. Can you add assignment via something like this in hgrc (if bitbucket username is johndoe):

#!ini

[ui]
username = johndoe

or this:

#!ini

[ui]
username = johndoe@bitbucket.org

The issue is :

• I don't want to add aliases to new repositories.
• I want immediate commit's author assignment.
• I don't want my e-mail stored publicly in raw commit.