Microsoft 365 for Jira offers various ways to speed up workflows and simplify communication. Answers to this question depend on the features used, the perspective (Jira user vs. customer), or the specific use case. Both apps have their benefits and are mainly just Teams apps you can deploy in your Teams tenant that are tied to your Microsoft 365 for Jira app license in Jira.
Here are just some examples to give you a little guidance.
TLDR
Use the Customer Portal app for your JSM customer users and the Smart Connect for Jira app for your licensed Jira users, or combine both.
Service Management Use case - Initiation by customer
Customer Portal app only
Most customers use our Customer Portal app in Teams to let their users raise requests faster and easier via Teams. Customers can view their requests in Teams without leaving the app. The look and feel closely matches the native Jira Service Management portal.
From Jira's perspective, licensed users start a chat with the reporter and add the Customer Portal app as a chat participant. This app posts updates and automates workflows, such as enabling a request resolved card with CSAT or sending approval requests.
Useful links
Use case: Internal ticketing with Microsoft 365 for Jira - Microsoft 365 for Jira - Confluence
Feature: Teams portal app - Microsoft 365 for Jira - Confluence
Service Management Use case - Initiation by Agents
Smart Connect for Jira only
Some customers prefer that users post problems in a Teams channel instead of raising requests themselves. Agents then manually create tickets, deciding which issues become work items.
To prevent users from raising requests directly, use Smart Connect for Jira. Only Jira licensed users can create work items or requests from messages. Messages can be AI summarized, allowing you to combine multiple messages into a comprehensive description for your work item or request.
From Jira, the licensed agent can easily start a chat with the reporter or requester or post back into the same channel.
Useful links
Feature: Create new issues based on chats/channel conversations - Microsoft 365 for Jira - Confluence
Jira Business/Software Use case
Smart Connect for Jira only
As a Jira user, you want to collaborate with colleagues on Jira work items via your software or business board and share them within a Teams channel or chat.
Use Smart Connect for Jira to add the board as a tab in a Teams channel. You can share this board with non-Jira users to make it accessible to stakeholders.
You can also post updates to the Teams channel where Smart Connect for Jira is installed. Posting depends on the preset and built-in automations you configure.
These features do not require the Customer Portal app.
Useful links
Use case: Campaign management with Microsoft 365 for Jira
Feature:
Search and share Jira issues in Microsoft Teams - Microsoft 365 for Jira - Confluence
Work with your Jira board in Microsoft Teams - Microsoft 365 for Jira - Confluence, Preset: Teams - Microsoft 365 for Jira - Confluence
Teams: Start a chat/channel conversation - Microsoft 365 for Jira - Confluence