It seems like a good concept, a way to carry all your EDC up and off of your belt, well hidden under a shirt, but still accessible. Also, it looks like you can carry plenty of gear with the extra pockets.
EDIT: Looks like it could be great for hiking. My only concern is the rubbing and discomfort it could cause against your midsection after a long enough period.
That looks tall and terrible. I know one of my friends who used one, as she was always complaining about the lack of belt loops and pockets on lady’s jeans. Didn’t hear the best reviews from her on corsets either.