The Jira Service Desk Configuration setting for Notifications seems to imply that it is possible to have Jira send notifications as configured per Notification Scheme to customers.

I can't find any reference relating to a clear explanation about the effects of this setting. I expect customers to receive notification as configured by the notification scheme. This is however not the effect when I started testing this.

Another user already shared his experience (see https://jira.atlassian.com/browse/JSDSERVER-5564).

Could anybody please refer me to documentation that explains the use case for this setting?
nb the learn more link is broken on Cloud as well