As others have aptly said, Barbara's character here shines as an amazingly complicated girl, despite her actual shallowness. You know exactly how her story will end long before the final scene, but wow, that dance at the beginning is just pure art. Not having been alive in the 50s, I was amazed that the censors even allowed it on the air, but they did, and I consider it a classic Hitchcockian scene. That alone is a reason to watch this episode. Everything about it: her beauty, the cute/sexy teasing dance, the rapt partygoer cast, the camera work, apropos music -all of it makes you simply adore and/or pity her. Then her subsequent behavior snaps you back to reality and you see her character for the shallow, entitled vessel she really is. It works because we all know someone like this. Unfortunately they're common today, but back then? Not so common, and quite scandalous.
As I said, the rest of the episode plays out pretty much exactly as you would expect, but that setup still makes it a very worthwhile watch.