In some cases, admins may want to change the default display name for portal-only customers (e.g., myname instead of myname@domain.com).

It would be nice if there was a setting that allowed you to toggle between the full email address and a partial email address (sans the at symbol and anything after it).

This could be for various reasons, but one particular reason is how some mail services will reject notifications if the user's email address is the display name as the receiving mail service may view this as an attempt to spoof the user.