The animation for the full-screen case serves a useful purpose: drawing the eye to the window in the preview.

The non-fullscreen (desktop) case uses an animation for the same purpose, locating the current app window in a sea of others.

So what would the preview be in the swipe-from-desktop case? A preview of the window-sea, or the desktop as is? What should the animation be? I suspect those questions are why they chose to just name the desktop.

I think it would be more consistent if the tab based preview only existed for the desktop window-sea and transitioned to the actual space previews when swiping between spaces.