Well, yeah. Also consider OBS crew are off duty from about 10 pm to 6 am. Coach attendants are usually out of their cars in their sleeping accommodations during those hours, unless there's a big late night stop, and SCAs often are. On Superliners, at least, in my experience, about half the time they'll go to transdorm accommodations during their overnight off-duty hours and do not stay in Roomette 1. A lot of the time only conductors are in the body of the train in the late night and early morning hours. The OBS crews are in their sleeping accommodations, often every single one of them in the transdorm.
T&E crews are forbidden from sleeping onboard. OBS crews are expected to sleep onboard and have off-duty time to do it.