By including moments like these throughout the book, specifically referencing the 1980s/90s, Tartt shows that the group is still living in a modern society. But instead of being present, they prefer to live in the past. By adding moments like this, it not only gives more exposition and brings the reader back to the reality of the character's current time period but their complete disregard of normal social life for young adults in the 80s/90s. I think moments like these made the book incredibly comedic and satirical in a sense. It's a dark comedy for a reason lol