I found a nice use for tabs with #niri: I have a number of browser windows open, with documentation and other stuff related to various ongoing projects. Each window is for a single project.
It became a bit of a chore to switch between them, because there was no indication of how many windows I have open.
So I collapsed them into a column, and enabled tabbing for that column. Now I see how many windows I have, and which one I have selected. Makes it much easier to find where I'm at.