In all honesty, if the devices aren't in use then they won't be drawing any power at all. They only do so when you insert media into them. So, it's no real advantage power-wise to remove them.
If you were talking about cooling and needing more space for airflow, then I could see an benefit to removing them under that scenario. Otherwise, they aren't hurting anything where they are. Where else would you put them? In a drawer somewhere where they'll take up space needlessly?
Even if there were a power concern, just pull the power connector from the back of each of them and, voila!, no more power to the device.
