Email This Issue for Jira Server provides a seamless email experience to enrich the collaboration toolset of Jira Server. There are various ways for sending outgoing emails using Email This Issue: manually, or with the help of event notifications or workflow post functions.
As for Outgoing Mail Connections, there are two possibilities. It is strongly recommended to use Email This Issue's custom Outgoing Mail Connection, however, using Jira's connection for sending emails is possible too.
There are some limitations when Jira's Outgoing Connection is set as the Outgoing Connection in the Context or in the General Configuration (for Bulk Email sending).
icons (e.g. issue type icon, priority icon) do not appear in some email clients
email's status cannot be retrieved for the Email Audit Log, only the "Sent via Jira" status will be shown
Jira's Connection won't be handled by Email This Issue's backup / restore functionality