Win+ijkl moves the window to the next edge with the "MoveToEdge" function, snapping it around the screen.
Win+Shift+ijkl grows the window from any edge.
Win+Ctrl+ijkl shrinks the window from any edge.
Win+Cursor switches desktops, Win+Ctrl+Cursor sends window to other desktops.
It seems intuitive to me because ijkl is used for actions within the desktop, cursor keys (reaching farther) are for between desktops.