I am not sure what you think the word aesthetic means. Aesthetic as a concept is about the style and the visual makeup of a thing — this means the aesthetic of a thing can also be ugly, dirty, distorted, weird, childish, funny, fucked up, silly, as many things in the canon of art history have been. Aesthetic as an adjective as it is used in daily life is somewhat linked to the idea of beauty, but the ideas of what is beautiful vary wildy not only throughout history, but between individuals as well. But I did not use the latter. Everything has an aesthetic. Yeah even cheap, consumerist, trash nobody seems to like.
I am not arguing I personally think tag smeared walls are aesthetical, but I argue that there are people who do indeed do. But most noise-protection-wall-graffiti where I live isn't tagged smearing. If we go by area easily 80% are big colorful motives.
Having known people who do these things I also know that for them the "where" is sometimes more important than the precise what and while the aesthetics won't convince me personally I can't say that I never asked myself the question: "How the hell did they manage to paint this thing in that location?"
And I don't see train stations on instagram, because I don't follow people who post them. But I also don't see couples posting their vacation photos or influencers selfies for the same reason. If I did follow them I would see them.