Localization has a major flaw. You can't localize your box art, thumbnail, or screen shots. Everybody says time and time again that box art is the most important item in selling your game, and I agree. Our box art says 'What The?!' in English across it, that tells French, Spanish & Italians that it is an English game. I can't fit 4 or 5 languages on one box, there isn't enough room. (Our game also has tons of spoken dialog in it to complicate matters, we never planned on doing a localized version of it, we don't have French/Spanish/Italian voice talent)
As you pointed out Harald, the actual trial downloads / purchases from these other countries is pathetic. Add to that the difficulty in development, translation, getting reviewers in other languages, it doesn't seem to be worth it.
Our non-English sales to date:
France 1 sale
Spain 2 sales
Italy 3 sales (Wahoo! 3 sales)
Even considering games that have done well, like ZP2K9 (I hate that name) only sold 2% of their games in non-English countries (
according to a Gamasutra article).
I suppose we could release multiple copies of our game, each copy to only one country, that way we could have localized box art (but we are not going to do this).