There are three places where email recipients can be configured for alarm notifications; the admin (C-Admin) user, in the Email Settings page and on the Automation level itself.
Additionally, it is possible to apply some filtering to allow specific users to receive certain alarm types and not others.
The effect of configuring email addresses in all three locations is additive. If you have three different email addresses applied to the admin user, email settings page, and one on the automation itself, then all three of those users will get copies of an alarm email.
The Alarm Settings page allows you to configure several categories of alarms that should be sent out to specific recipients, but only under certain conditions.
Email recipients that are configured on the Email Settings page have no way to filter alarm categories and will receive all alerts.
Email recipients configured on the automation level and the admin user, however, can be configured to receive specific email categories on the Alarm Settings page.