[zdragnar]

In the case of language learning, the external motivation provided by gamification is supplanted by the external motivation of having access to conversations, music, movies and literature that you previously didn't have access to, or required third party interpretation to appreciate. Being able to converse directly is a massive boon in the right situations, such as when travelling where you need to know the language to get around, or when your coworkers natively speak that language but not your own.

Discipline is well and good, and if you're willing to put in the effort to become better disciplined to push through difficult things, I agree that you're probably better off. I do not agree that someone who already has that level of discipline would be hurt by a gamified system, though. The rewards of gamification on their own are fairly minimal, as they merely provide a (possibly false) sense of progress independent of their own assessment of how they are doing.