What is the difference between "Show desktop" and "Plasmoid view"?

I binded a shortcut (Meta-D) to the "Show desktop" plasmoid button.
With that I was able to hide big windows which overlapped my plasmoids. (In fact I keep plasmoids on the desktop. I do not use task panel.)
Recently I found that there is another shortcut, Ctrl-F12, which does a similar thing (a label appears at top: "Plasmoid view") (in Hungarian language, so it may not be verbatim).

"Plasmoid View" is known as the Widget Dashboard, and by default brings the widgets you have on the desktop to the top without affecting the order of your windows. However a setting is available that makes the Dashboard independent from the desktop allowing different widgets to be present.

Show Desktop minimizes all windows currently shown on screen, which the Widget Dashboard does not.