That’s what I did (and with one USB cable swap and a button press on the monitor, I can switch keyboard, mouse, monitor, speakers, and camera between them).

But the key for me is I do that because I have a work laptop and a personal desktop and I want no question about the ownership of things I do on the desktop.

This. Employers tend to give out laptops for home use, not desktops. I'm not about to use my personal desktop for work, or my work laptop for personal stuff.

When I disconnect my laptop to work from another location I have all my open files in the same place, all my shells alive and ready to re- ssue their last commands without fiddling with a large history file.

I organized my windows and tabs and splits in such a way that it degrades gracefully when I switch from the external monitor and back.

How often often do I really need that? Not often, but when I do it's really useful.