I'm not sure if this is a poor implementation or a poor application
Probably a little of both, but I think it's really cool. I could see it reducing eye strain over the course of a day while you're working at a computer. Right now you're always moving around but the text size stays static causing you to squint.
Wouldn't it be cool if it took your vision into account as well and adjusted focus (or whatever; I'm not an eye doctor!).