My main concern is the fact that them being black there would be very little to no actual light cycle for the ball pythons inside the system. Also the thickness of the tubs could reduce the efficiency of heating pads/heat tape underneath the tubs. But I am really not sure on that.
I use one as part of my enclosure and I think it works great. You'd probably want to leave a gap at the top to allow in light. I didn't leave a gap, but my snake has the option to come up into an open terrarium.