I don't know for genZ people but I use my last disposable camera in 2010. Althought, I must be honest I had stop to use them for more almost two years in favor of the more common digital camera.
Either way, I think we can agree that millennials know what film is. Many of us have even developed it ourselves. You know back when people were thought things other than app development and learned helplessness.
Seriously, I remember taking a disposable camera with me on our school trip Washington. I also remember that it was during that trip that we all found out you could open those things up and turn them into mini tasers.