Maybe there is a difference between active and passive retina stimulation in terms of ability to correct myopia? From the article it sounds like they are still determining if they can actually cure myopia and how long the effect lasts. Of course, at least in the US, how they are able to market them depends on what they get FDA approval for.

Perhaps if they are given to children, it would result in them permanently developing 20/20 vision.

20/29 isn’t some perfection. It’s merely typical. Many people with good eyes can see quite a bit better than that.