Docs: Add use cases for linked epics

What does this MR do?

Adds use case topics to https://docs.gitlab.com/ee/user/group/epics/linked_epics.html based on Epics linked items widget - update docs with us... (#407465 - closed).

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doc/user/group/epics/linked_epics.md

@@ -18,6 +18,86 @@ When you try to close an epic that has open blockers, a warning is displayed.
 
 To manage linked epics through our API, see [Linked epics API](../../../api/linked_epics.md).
 
+## Ways to use linked epics
+
+You can use linked epics to solve several planning and coordination challenges.
+The following examples show how linked epics help teams work together more effectively.
+
+### Cross-functional initiatives
+
+Use linked epics to coordinate work between multiple teams and track interdependent deliverables.
+When teams work together on a large initiative, each team can manage their own epic while maintaining
+visibility into related work.
+
+For example, when launching a new feature, development and marketing teams often work in parallel.
+The development team tracks technical implementation in their epic, while the marketing team plans
+promotional activities in a separate epic.
+
+By linking these epics:
+
+- Teams can track dependencies between technical and promotional work.
+- Each team maintains autonomy while staying aligned on the broader initiative.
+- Stakeholders get visibility into the full scope of the launch.
+- Teams can identify and resolve blockers across organizational boundaries.
+
+This coordination helps break down silos and ensures all aspects of the initiative stay in sync.
+
+When you link epics across groups:
+
+- Each team keeps their work in their own group.
+- Teams can see related work without switching between groups.
+- Status updates automatically flow between linked epics.
+
+### Dependency management
+
+Use linked epics to manage and track work dependencies.
+When development can't begin until infrastructure changes are complete, linked epics help teams
+manage these dependencies.
+
+For example, when building a new feature, teams often need infrastructure updates
+before development can start. The infrastructure team tracks their database migration work
+in one epic, while the development team plans feature implementation in another epic.
+
+By linking these epics:
+
+- Teams can track when infrastructure work is ready for development.
+- Development teams can better plan their sprint capacity.
+- Product managers can identify potential workflow delays.
+- Teams stay informed of progress without constant meetings.
+
+This visibility helps teams complete work in the right sequence and avoid blocked tasks.
+
+When you link epics to show dependencies:
+
+- Infrastructure and development work stays connected.
+- Teams know when they can start their work.
+- Status updates flow automatically between epics.
+
+### Higher-level planning
+
+Use linked epics to connect short-term execution with long-term planning.
+When managing a series of releases, you can organize high-level goals and track individual feature
+deliverables.
+
+For example, when planning multiple releases over several quarters, you can create separate epics
+for each release.
+Then link these release epics to a central roadmap epic that tracks the overall project.
+
+By linking these epics:
+
+- Teams can understand how their work fits into the larger strategy.
+- Product managers can track progress across multiple releases.
+- Teams stay focused on current work while seeing future plans.
+- Stakeholders can monitor both granular and high-level progress.
+
+This structure helps teams progress on current work while maintaining broader goals.
+
+When you link epics for planning:
+
+- Each release's progress is visible in the roadmap.
+- Teams can see upcoming work early.
+- Status updates roll up to the higher-level view.
+
 ## Add a linked epic
 
 > - Minimum required role for the group [changed](https://gitlab.com/gitlab-org/gitlab/-/issues/381308) from Reporter to Guest in GitLab 15.8.