But the reason some like multiple desktops is that you can have several totally unrelated activities going on, involving multiple applications & documents, but they can be segregated to separate desktops so that one group of tasks doesn't interfere with easily accessing another group of tasks.
I usually knock the virtual desktops down to 2 or 1, but I sure wish that I could do the same natively in Windows quite often. I don't remember particularly caring for any of the multi-desktop solutions for Windows, but I've used them on and off since Win98.
Mostly, it depends on how much stuff you might have going on all at once.