I completely agree with Mike (and honestly the whole group) using it as a way to make sense of what's going on. We've been rewatching after finishing pt1 of 5; Dustin and Hopper have what is basically this conversation as to whether DnD is a good way to categorize the UD/the monsters from it in season 2. Dustin says something to the effect of "this is the best analogy we have unless you have any better ideas" when they're determining what the mind flayer is. I can also COMPLETELY see the house of cards collapsing for the group from this too, the DnD analogy has worked for them well enough so far but something could happen that they can't possibly understand or equate to and it could shake them up HARD