Hi Jenny,
I think it is just another layer of flexibility for customizing notifications.
Depending on how many application or forms you have in SN, you may want, for example, all tickets (IT, HR, Change...etc) to have a header and a footer with your company logo and ticket information in the header, and the links to the self-serve portal and intranet (for example) in the footer. The body (the in-between info) of the notification will have slightly different variables/requirements from IT to Change management for example.
So you can use a layout for the header and footer images or links, and add it to every template for your organization, and then add department logo/standard ticket info in the template for all notifications for that specific department (for example). You could argue that you could just put everything in the template, and change the body on the notification itself, which you could, but then you have that additional step of finding the right template to clone, and changing it based on your need.
Either way, they are both correct methods, and you can use whichever best fits your needs.
