Normally, this is a bad idea, because the IGG and curse piles run out simultaneously, and you don't want to be messing around with bad cards like counting house when you're supposed to be winning the race to eight duchies.
However, occasionally there is asymmetrical cursing, e.g. if your opponent opens sea hag and you decide to buy IGGs, or due to watchtower. Then the curse pile will empty, but, if there are, say, 3 IGGs left, that second pile is very unlikely to empty, and the probability of a quick three-pile is the same as in an ordinary sea hag game. In this event, counting house goes really well with the IGGs after the curse pile is gone, the point being that you can have your cake and eat it too with the extra coppers. Agree/disagree?
Related question: I don't think there's consensus yet on which cursers can be skipped for IGG (my wild guesses: skip sea hag, don't skip mountebank and familiar, otherwise ??).
Basically, I don't understand IGG at all. Say anything helpful.