When I used to practice divorce law, it was necessary to obtain a photograph of the other spouse in order to help prove service of the court papers. I always thought it particularly sad when my clients would provide me with a wedding photo for that purpose.
We sure did! Collected them in the empty paper roll bags and they were picked up by the courier who collected any Kodak outsourced work. (Minus those precious AAs!!)
If you took the time to remove the cardboard they actually have those little recycling numbers on them - guess they got used again and again - but maybe not necessarily as "single (multiple) use cameras". . . . . .
I consider my Holga one of my best cameras. I shoot black and white nearly exclusively, and the camera has no discernable light leaks or issues with the back falling off. All I've done to it is put a tape flap over the red window to prevent the light from bleeding in.