Counterpoint: different tools and tasks have different requirements for interaction. Each tool provides an interface specialized to its workflow, and the hierarchical nature of the system allows me to split even inside the same tool for different workflows.
My primary window-organization tools are: i3 virtual desktops, web-browser, emacs, and tmux. i3 virtual desktops are named by task/workflow: I have one desktop for project management, one for emacs, one for terminals for one project, one for terminals for another project, one for work-related communication, and one for personal communication. Emacs does its thing and makes great use of it, but its spectacular profusion of buffers and its insane customization never pollutes the rest of my WM because it's contained within emacs. The browser desktops group related tabs, but they go one further and let me put tabs side-by-side without multiple windows of project management polluting my global window list. And so on and so forth.
Allowing each tool to specialize information management for its particular use case gives me much better performance overall. It's definitely specialized and idiosyncractic; I would not want to make everyone deal with it. But for me, doing this 8+ hours a day: every time I'm forced to work without that hierarchy and that specialization, I can tell you that the effort is worth it.