I also think that some crews bring food along to avoid buying it at the destination so that they can keep their per diem as a form of extra pay. Hotel restaurants can get pretty expensive pretty quick (and probably more than most per diems).

That being said, the real question to me is: should FAs be able to bring so much luggage along (or at least be required to check some). I've had numerous instances where I'm the first one on the plane, and already two entire overheads are taken up by crew bags. I've also seen many FAs getting on the plane with four(!!) bags. They should be required to check extra baggage just like the rest of us (especially since it would be gate valet and they would get it back in the jetway). It just irks me that FAs get to bring an unlimited number of bags along when overhead space is so limited.