Things like per-window or per-app settings:
- borderless
- opacity
- default an app to a virtual desktop, position and size, even sub-types of windows (e.g. when you want children to appear in some designated place)
- a few well-placed magnets (sides, center, other windows) to quickly resize 'perfectly' (my OCD loves it haha)
- activities (more like a meta-organization, so powerful when switching tasks/context like home / work / hobby / etc.
- custom shortcuts for anything (any of the above, launch any app, optionally with command-line options)
and so much more...