The downside is that they are most definitely not designed for anything other than their original purpose, needing a chunky 12v supply and being rather bulky.
Other people in the Open Source Community did the groundwork in working out how to strip down Kinects long ago to remove the pose detection processor and reduce it to just the RGB-D depth camera.
We've gone through this process ourselves and made a scratch built power supply and USB connection in the past but decided to develop a small breakout that makes the end result tidier. Not being a priority the boards have languished for months but today we finally put one together.
We're not convinced this is viable as a product but it works and was a fun exercise. We're going to build a few units for our own upcoming robotics projects. With used Kinects being almost throwaway cheap you can afford to add one to a project and just leave it in place, unlike modern machine vision cameras.