Review (5/5): It does indeed reduce chipping and peeling.
It feels a bit weird and different than the metal file I'm used to, but it works. I've always had problems with my nail tips peeling and chipping and yes I do file in both directions but I don't see how it's possible to get your nails to be symmetrical filing in one direction. So as advertised the glass file leaves me nail edges smoother and less prone to chipping even when I file in both directions. I did find it a little odd. The file came in a little vinyl sleeve, but the sleeve doesn't fit into the included tube holder. I guess you have to choose which case to use, but neither on it's own seem like great protection for glass.