I remember hearing (on a podcast IIRC) that WiiWare and DSiWare are commonly used by developers to build up a portfolio. XBLA has insanely high requirements before they let you in, WiiWare doesn't so developers make WiiWare games to get the attention of the big publishers with access to XBLA and PSN. That's why you see so many games migrate from WiiWare to other platforms, the developer was never really planning on making money on WiiWare.