You guys are misreading the facts. It doesn't say it helps your eyes if they're in need of correction as it is.
It's just saying that it'll help your eyes to distinguish between minute changes in colour. In this example they said grey. I've got great hand eye co-ordination, as well as better than average vision (according to the eye doc). And that came with playing video games. However, it only helps to a point. As far as I remember, playing on a bright screen, with the lights off actually hurts your vision because it strains your eyes.