These, specifically, compete with Osprey and Nathan and to a lesser degree Camelbak for the ultrarunning/lightweight technical venture market. The front pocket arrangement is to allow easy access to bottles and to put phones and the like in the front pockets and be able to access them while running.

They're useful if you're climbing, running, rappelling, or some combination thereof, and so on. You can use a regular hip belt with stuff on it without it interfering with the backpack, which is kinda nice, and they don't interfere with a climbing or sport harness. The other competitors in this space are the Nathan Crossover 15L and Osprey Duro 15L, if you want to cross shop.

You don't get the NBC fittings Camelbak sticks on their stuff (which, fine; I'm not planning on needing to rock the Tyvek suit while hiking, for the most part).

I ran across the grand canyon - twice - in about 13 hours with the Osprey competitor to this pack, and should you ever feel inclined to go visit places where movies like "127 hours" were filmed, pretty much all the outdoors-people are going to be using something like this, because slot canyons, running water, and climbing/scrambling all do a lot better with something thin-profile.