I think a single monitor is one of the main reasons to use a tiling window managers, especially if it’s a large display. That’s my setup now, after years of using multiple monitors:
If you spend a lot of time in Excel or other text-heavy or coding apps, two monitors can make more sense. But in my case, about 95% of the time I only use one app at a time. For me, fast workspace switching is the real benefit of a tiling WM, with tiling itself being a bonus for the few times I want two or three apps on one screen/closer together/side-by-side.