In a design that can only be explained as a designer trying to cash in on two of the biggest eco-trends out there--bicycling and water bottles--the BottleClip allows the cyclist to attach a water bottle or container of his choice to his top tube and hang it down like a pendulum. Simple but useless, the BottleClip snaps onto the tube and allows one to screw in a standard water bottle to carry it along for a ride.
While it certainly catches the eye, the BottleClip seems to make more problems than it solves. There's really nothing wrong with the standard water bottle cage for carrying a water bottle. In fact, it could fit that very same bottle in the picture, along with your average BPA-free bottle that doesn't feature a tapered, screw-on neck. If you don't like the water bottle cage, you use a hydration pack. Either option is far more functional than this.
I'd imagine a bottle dangling like that would swing back and forth hitting your legs every pedal stroke, so not only is it structurally inferior to what's already available, it's impeding the very activity it was designed for. It also looks like it'd make for awkward balance.
I suppose that the design does invoke some thought, which is what designs do. Unfortunately that thought is limited to an incredulous wonder as to why such a inefficient product would be designed in the first place. I can't quite come up with an answer.