Looks like tiling window managers have either workspaces or tags and the two terms are not interchangeable.
Workspaces, in i3wm at least, are attributed at startup one per monitor/display, and then can be added per monitor/display.
Tags, as in Bspwm, awesome, and DWM, are a bunch per monitor/display at startup. However, a single tag is displayed per monitor/display, as if the tag were a workspace.
In i3wm, a window belongs to a “container” in a given workspace. The user sees the window when viewing that workspace. The same window cannot appear on multiple workspaces at the same time.
In tagging window managers, a window can be tagged with multiple tags and then, when viewing a tag, the same window can appear e.g. maximised in one tag and tiled among other windows in another tag.
The container logic in i3wm always felt like a limiting and restricting facot for me, while the tagging feature has immense productivity potential.
Todo: Find a way to emulate window tagging in i3wm. Still sticking with i3wm as its statusbar lists windows and other data exactly as I want it and unfortunately this statusbar does not work in other window managers…