When an administrator manually registers a member for an event, and then clicks the "Send Notification" button, the resulting "registration confirmed" e-mail does not also go to the organizer per the mail routing rules defined for the event's "registration confirmed" e-mail settings. Furthermore, the "Send Notification" button also doesn't give the administrator a way to add a CC e-mail address to the notification, or a checkbox to allow the organizer to be CCed.

In short, this is inconsistent with the event settings and adds to the work the administrator needs to do - they need to manually inform the organizer of the registration, and the organizer doesn't get the information normally included in the "registration confirmed" e-mail they get copied on when a member registers themselves. For large events, this is a lot of unnecessary work for all involved.