As i switched to a minimalistic tiling window manager, i more and more saw the value in them.

I have by default 9 virtual desktops, use different ones for different tasks.

Instead of minimizing/maximizing windows i just switch virtual desktops. It perfectly suits my work flow.

In my opinion: 2 monitors instead of one and quick shortcut switching through virtual desktops, developing some routine in using them, definitely boosts ones productivity.

But have to admit that i also didn't quite see value in them while using full Desktop Environment.

Regarding the question of Microsoft not implementing the feature in Windows:

Since the typical Windows User is a heavily mouse dependent one, i think they can do without it.

Hint: Change the title from "Ubuntu workplaces" to just "workplaces" or "Desktop workplaces". I don't see how this is Ubuntu specific