Think about it, you can play from the comfort of your bed or couch. The controls of Spiral Knights aren't all that complex either, so it could work with the Nunchuck + Wiimote or Classic Controller Pro. The game would be available as a free download on the Wii and it would function the same as it would in a web browser or Steam. I mean, if Three Rings/Sega are making trading available via Steam, imagine the partnership they could make with Nintendo, plus the fact that the Wii has the largest market share of consoles (not to mention the coming of the Wii U). The motif of Spiral Knights fits well into a Nintendo library anyway, seeing as the gameplay is heavily inspired by Zelda/Bomberman.
So?
If you want to use a controller to play, sk supports that already.
I like my mouse and keyboard better but sometimes i'll use my xbox controller, works fine.