I think it depends on language.

Here in Dutch, it depends on the context. For example:
Dit spel is voor Wii. - This game is for Wii.
Dit spel is op de Wii. - This game is on the Wii.

Personally, when I write here, I usually just apply my own 'Dutch' rules as that's the most convenient to me. I don't know if such rules exist in English language too. Or why they exist in the first place and what the logic is. I'm not a big language-buff, I only know English because I've been playing games for a million years now.

But anyway, long story short, 'Who cares but I dunno.'

It's like that across consoles, really.

"Devil May Cry 3 only for the PlayStation 2."
"Resident Evil was on PlayStation and Sega Saturn."

The use of an article depends on how you are using the word.

Wii U is the name of Nintendo's next system.

Using it as a proper noun which doesn't need an article simularly:

Apple makes many electronic devices.

The Wii U is coming out on November 18th.

This is using Wii U as an adjective/adjective clause, in English when the noun is know to the audience you can drop the noun leaving the article.

The game system, Wii U, is coming out on November 18th.

I used Wii U as an adjective clause because it sounded better then the The Wii U game system.

The Apple corporation is based in the United States.

I think this explination is correct, it been awhile since I had to explain retoric (grammar rules).