The owner of a mark with a sufficient reputation can take action against dissimilar goods and services where they're riding on the goodwill of the mark of course so TMs are not completely limited to their classes.

Rolex could sue me if used their marks on a good which they weren't registered in if I was trying to take unfair advantage of their mark, tractors for example.

Whilst it's highly unlikely in this case that Apple would, I think it's inappropriate to seek protection of the term in the first place, at least from a PR perspective and from the risk of trade mark creep.