With a tiling WM (like i3), most of the time the whole screen is used. So, currently I have Firefox open full screen. But if I do decide to open another window in this workspace, it'll nicely cut the screen in half and put them side-by-side. So, if you are a mostly-fullscreen person, then the tiling WM workflow might do what you want automatically, more often.

Sometimes it feels sort of like using tmux full screen in a terminal, but some of the panels can be firefox or a PDF reader, haha.