It is interesting, I don't think it will actually help them much. If you have Foxtel already you can likely get the whole of showtime for around the same price your paying on itunes for Game of Thrones. (While the season is going and there are day 4 eps a month.)
Not sure they are going to convince people that don't have Foxtel that they should pay $60+ a month for the service purely on the back of Game of Thrones.
Especially since the only part of the market they can hope to capture with this move is "people who already pay for game of thrones legally over itunes". I would think that most of those people also know how to torrent but choose not to and foxtel just pissed them off, I doubt they happily switch services.