I think you're 100% correct. But, I also think that even implying that that is the purpose is itself a form of signaling of your wealth/social class. "I'm much too smart/frugal/down to earth/in the know about where the real good food is to be fooled by cloth napkins and dim lights." Signaling is funny like that. We often discuss it in the context of letting others know how up the social ladder we are or want to be perceived as being. But at least as often signaling is used to convey to others that we're not at the top, we're right where we belong, with the other members of our tribe.