It's stupid to have a huge monitor (or monitors) and then use only a tiny fraction of it. I don't need a little window showing a few lines of text to be any bigger than it needs to be.

You should try it.

I've used an Android phone plugged into a monitor before when I had nothing else. Doesn't work for anything but the most trivial of situations, which IMHO says just how much work you actually do and how much information you actually use in your work. I need to look at multiple documents simultaneously to compare and refer to them. Switching between windows all the time and trying to memorise what they showed for a second or two is a stupid inefficiency.