Free versions usually only handle milestones (diamonds). Pro+ handles (bars), milestones (diamonds), and dependencies (arrow lines linking them). You can visualize a critical path directly inside a PowerPoint slide without exporting a static image from Visio.
Imagine you have a project schedule in Excel. In the standard workflow, you would create a chart in Excel, screenshot it, paste it into PowerPoint, and find that the text is too small to read. You then manually draw shapes in PowerPoint to make it look better—a process that can take an hour. office timeline pro version