Split View and desktop tiling can both place windows side by side, but they live in different navigation models. Split View creates a dedicated full-screen pair. Desktop tiling arranges normal windows while the desktop context remains available.
Use Split View for a dedicated pair
Choose Split View when two apps form one sustained task and you want them isolated from ordinary desktop windows. Enter through the green-button menu or drag a window onto a full-screen app in Mission Control. The pair appears in the Spaces bar.
Switching away and back follows full-screen Space navigation. That can be helpful for focus and inconvenient for frequent drag-and-drop with a third app.
Use desktop tiling for flexible arrangements
macOS tiling supports halves, quarters, fill, and multi-window arrangements through drag regions, the green button, menu commands, and keyboard shortcuts. The menu bar and Dock remain part of the ordinary desktop model.
Choose it when you need more than two windows, expect to resize often, or want nearby overlapping windows.
Test the real task
Compare the same task in both modes. Check access to a third reference, menu and Dock visibility, movement between Spaces, window margins, and what happens when one app closes.
Neither mode organizes the windows by project or saves their underlying resources. Add a project label or durable link only when that separate problem exists.