I'd say daily stress links to insomnia. Work deadlines, exams, etc etc and THAT leads to playing more games.

In real terms I can see how gaming may some how ever so slightly affect a persons speed of going to rest HOWEVER I think its marginal based on how stress and other life activities would affect our sleep patterns.

So... even though the article may state that it adversely affects sleep I would argue the point that gaming may bring a person to a more relaxed state after daily stress which actually in turn benefits your sleep pattern.