I wind up using dual monitors for cross referencing applications, where one screen has a drawing in AutoCad, and another screen for modeling hydraulics (a calculation app) and a pdf of a pump curve. Quad screens I have used for control of process units (chemical plant).
I’m sure you agree, can’t get enough real estate.
I want one of these huge touchscreens:
https://www.youtube.com/watch?v=XLduqQTMSso
(I lust after the screens Tony Stark uses in the Iron Man movies, and yes I know they’re just CGI)