I'd say it's a good thing that so many kids actually read a book...and in Harry Potter, the "value" of what they are reading is not that bad either. Of course it's just a fantasy story, but it's surely a lot better than most of the stuff kids these days read (if they read at all).
They might even get into reading through the HP novels and might go for Tolkien next...that should give their vocabulary quite a shove in the right direction...
