My perspective is: Workspaces dedicated to a single app makes no sense for tiling WMs. That workflow is fine on a floating WM.

Where tiling WMs shine is when actually tiling windows. For me it's the holy trinity of Browser, editor and terminal all visible at once, and navigatable spatially via super+hjkl or super+up/down/left/right. So I have one workspace per project which makes a lot more sense to me as an actual workflow for tiling WMs.

Niri just improves on this substantially by allowing new windows to open to the right, instead of messing with the existing layout in the current workspace. For example, if I need to open a pdf or something. I get to keep the holy trinity, but swap over to the new window easily.