Microsoft introduced the ability to rename your Microsoft account by creating an “alias” which allowed users the ability to receive email. However the alias account didn’t allow for logging in since it wasn’t a full fledged priviledge account. When the renaming feature returns it will bring along with it enhanced Alias accounts which will give the user the ability to log in as well.
Supposedly all aliases will use the same password and you can send and receive email from each of them. This solves the most problematic thing about aliases. You used to have to reset your password anytime you created an aliases.