I only use one monitor. I switched to a big screen TV-as-monitor because I was squinting at the screen on the regular sized monitor, and when I made the text large enough to see clearly at desk-viewing distance, the scroll bars kicked in requiring me to mouse around in order to see everything.

At least with one large screen I can make the text large enough to see and there's still enough screen left over to keep the whole page visible

There is a loss of clarity for reasons already mentioned... but for me its an acceptable tradeoff since I can read a large fuzzy word better than a small clear word.

YMMV.

also my bifocals required me to tilt my head back at an odd angle in order to make the smaller screen readable. I don't have to do that with the TV sized monitor.

https://www.dropbox.com/sh/ey71h8ep047758h/AAC12jNM0Hz9Q8zsh5iDeqNHa?dl=0