Looks shitty if it's even slightly dirty, gets dirty if you so much as look at it, requires very thorough cleaning to make it look good (no smudges or streaks).
Means you don't do your own cleaning—like, at all. Once-a-week housekeepers can't keep a mirrored coffee table looking tidy. Probably also helps if you have whole rooms you barely use, but even dust'll have it looking shabby faster than, say, wood. If you buy such a piece and do your own cleaning—and especially if you actually use it—you'll probably regret it in a matter of days.
It's the kind of thing someone without that can only own (without it looking way worse than almost any alternative material) if they're so dedicated to it that it'll be the thing people remember about them. "Aunt Gertrude and that damn table. You remember that? Wouldn't let anyone touch it, and damned if every time you came to visit, she wasn't cleaning it. She had a whole process. Drawer of different towels, three or four cleaning bottles she had to put on in order. One time my kid touched it with a cookie-greased hand and she saw me getting the Windex, nearly bit my head off."
The insight on mirrored surfaces was especially interesting. I remember seeing a staged photo of some Trump kid & spouse with their own kid playing in a living room with a spotless mirrored table and was like "oh, hey!" Lots of fun bits like that.
... Actually, the entire Trump thing was fascinating with Fussell's instruction guiding one's experience of it. "Prole" fit on expensive suits. Middle-as-fuck taste in home decor ("if you're rich it means everything's huge and covered in gold, right?"). Still haven't figured out how much of it's genuine and how much of it's an affectation for marketing/personal-branding reasons.
He got his hope-for-the-future "Class X" all wrong—just an upper-middle youth fashion wave, mostly—but otherwise it's still a surprisingly-useful tool for analysis, considering how old and half-jokey it was.