I use it to have a black “frame” around my laptop’s (built-in) screen. Don’t bother asking why, it’s just a habit I’ve gotten into. I can’t stand thin-bezel screens.
These are my usual settings, and they suit me.
The problem:
When I connect a setup of 2 monitors (via a usb-c dock), the screens are detected, etc… BUT the configuration of the integrated screen of my laptop changes, it’s extremely annoying:
The scale changes (125% —> 100%) and the “Adjust for TV” option is not applied… It annoys me!
I believe GNOME regenerates the monitors.xml every time an unknown display is connected. This forces me to reconfigure the displays every time I connect my laptop to a monitor setup.