Does anybody use the Backlog function within Portfolio Plan for waterfall projects?

​@Machaela Milburn the Backlog view allows you to view and manage Action Items. These can be used in any type of project. We recommend using Action items as it allows you to elevate the level at which you manage the Plan/Schedule and keep the detail in Action Items. The Plan/Schedule should be at the level that drives overall dates, duration. milestones, resource assignments, costing and actuals hours tracking, while Action items manage the detailed activities/tasks. When using a connected ProjectPlace workspace, the Action Items become cards in the workspace and the team get a Kanban to do their detailed planning and tracking.

These principles are detailed here:

https://success.planview.com/capabilities/Project_Team_Delivery/01.Get_started