IMHO ideal computer use is to move things in front of your eyes instead of moving your eyes/head. Your area of focus is quite small with almost no value to filling your peripheral vision.
If I could have one screen per application and surround myself in a galaxy of windows, I definitely would.
Would I look at them all on a regular basis? Of course not. 80% of them I would only look at once every hour or so.
So many big wins. I can do a zoom screen share on my main window and have notes, private stuff on the side window, I can read documents that often are vertically formatted on the side window.
I do a fair bit of comparing type work where I need a reference index doc on the side, then I got through the individual docs for tieback on the main.
It's game changing to have multiple monitors and particularly have one portrait and one vertical.
3D in 3D is different. And when you put 2D screens into a 3D digital space viewed as embodied in 3D XR you still get affordances you didn't have before. Sure you need to reimagine and rewrite from the ground up these long established and stable 2D apps, but there are places where real gains are there to harvest.