If phones consistently gave you a useful desktop environment when you plugged them into a monitor, I imagine that might change.

I think offices are the most likely places to have something like this, though. My company has monitors with USB-C dock inputs set up at each desk; you grab a desk and plug your laptop into it when you get there. But they're just using DisplayPort Alt-Mode, and a phone with a desktop mode would work with them as well.

I wish I could do that for work; would save me from lugging around a rather heavy laptop. :)