Sounds interesting, but I still think I prefer using workspaces, simply because I can set window rules for predictability.
I never want to / have to wonder where any particular window is. Every app will always open on the same workspace, in the same position that I define + a scratchpad workspace for random one-offs that I keep floating. I'm only ever 1 key press away from exactly what I want. I know that ctrl+b gets me my browser, ctrl+t gets me to my terminal(s), etc. I don't even think about the workspace numbers or layout beyond initial configuration. Zero animations, instant switching.
In your example, if I'm on one workspace working and I need to open Gimp, I press my keybind for Gimp and it opens on the scratchpad and switches to it immediately.
It takes a lot of initial config and tweaking as you go along but once settled it's the most efficient way I've found to manage windows, in that, the windows manage themselves i no longer have to think about them at all.
That makes sense if you use application per workspace, which never made much sense to me.
I'm often working on 3+ codebases or projects at the same time, each project has a browser window with associated tabs, an instance of an editor, several terminals. So they get a workspace. "Switch to browser workspace" makes no sense if there are 3 instances of the browser open, especially when I want the browser next to my editor for live reload/API docs.
The problem with your example is that you might have Gimp, a browser with its own set of tabs, and other multi-instances of apps needed in multiple workspaces as you work on multiple projects.
In Niri, you just have these open in the each workspace off to the side. And you know exactly where each one is.
In your example, you either have to flip through multiple Gimp instances in your scratchpad or you use tab/stack containers to tile them in to existing workspaces. But you are multiple keystrokes away now because you have to go to the container and paginate through it.
I never want to / have to wonder where any particular window is. Every app will always open on the same workspace, in the same position that I define + a scratchpad workspace for random one-offs that I keep floating. I'm only ever 1 key press away from exactly what I want. I know that ctrl+b gets me my browser, ctrl+t gets me to my terminal(s), etc. I don't even think about the workspace numbers or layout beyond initial configuration. Zero animations, instant switching.
In your example, if I'm on one workspace working and I need to open Gimp, I press my keybind for Gimp and it opens on the scratchpad and switches to it immediately.
It takes a lot of initial config and tweaking as you go along but once settled it's the most efficient way I've found to manage windows, in that, the windows manage themselves i no longer have to think about them at all.