At the time (well over a decade ago) there was still lots of skepticism around recharagables and the extra process involved in dealing with them... but the tech has gotten lots better since, at that time even low-self-discharge was sort of hard to find. I'm sure much of the industry has moved over by now.
I would love to end the senseless waste in surgery, but The Powers That Make Our Lives Suck For No Reason want everything to be single-use sterile objects.
The batteries are in a separate container that is attached to the bag of saline used for irrigation. It’s not in the surgical field.
Note that legally trash is still owned, usually by the person or entity which produced it, so it’s technically stealing. (Whether anyone cares is a different thing. If you picked bank letters instead of barely used batteries…)