… if you know how to use virtual desktops and shortcuts. You can’t look at two screens at a time, anyways.
One use case I can understand is having a 2nd monitor for checking stock prices or checking for a certain event. Other than that, I don’t see how it contributes to “productivity” while working or coding for example.
P.S: Tiling WM users may understand this post more
If 1 is more than “enough”, how many screens are enough then? Technically, if you never need any visual feedback from what you’re doing with keyboard and mouse, then zero screens would be enough.