I don't see culture as useless. To the contrary, it is a large part of what cohesively holds together any society intellectually, spiritually, and/or emotionally. Aesthetics are not useless, either.
I really get annoyed when people call art and culture useless. The point of learning "high culture" as opposed to low culture is to study common themes in humanity cross societies and through the ages. It is a part of comprehending our human existence.
Well, that's a bit different and beyond simply collecting cultural information. Your point here involves people analyzing that material. Maybe that could be the difference between its "social status marker" function and its "useful benefit."
I don't know how to explain the culture of my city. It's in limbo, region-wise, we pretend that we're French when we're all German or Black or Italian, and there's plenty of beautiful museums and parks and architecture, as long as you know which streets not to drive on at night.
-Carefully taking sips from the Fire Hose of Knowledge
Thus, I'd say it's not only a question of snobbery, about who is "chic" or not. It's probably far more complex, because as many sociologists showed it (for instance, Pierre Bourdieu), individual taste is almost always linked to Identity (And hence, as Magic Poriferan mentioned, to social class). This is the theory of Cultural capital.
I dunno, I can just appreciate a cultural artifact just for its amazement alone. I hardly go to museums, but the only one I ever really really wanted to go to was the King Tut exhibit. It was at the LACMA, it was pretty amazing. There was this knife that King Tut had, it was designed with such detail and amazing craftmanship. You can tell the reason it was so well made was because they took the "afterlife" so seriously. That knife helped him navigate the "afterlife". Hence, why it was made so well.
I think my main thing for art is its historical cultural value. You can see through art and artifacts, how societies ran across the same problems that our societies run into nowadays. Whether it be sexual, familial, spiritual, revolutionary, class struggles, etc... and you can see how they dealt with it. To me, that is the most interesting aspect of art or cultural artifacts. I think for me, thats why I can view Peruvian or lost Amazonian or French art as potentially similiar "value".