These things give us a "free from judgement" way of talking about our prides and failures.

If you say: "I do x thing great and x thing bad, because I'm a Taurus," the conversation can move on.

If you say: "I do x thing great and x thing bad because I'm just that way," you'll be simultaneously bragging and then having a conversation about how to fix "x thing bad."

MB and Zodiac signs are a very pragmatic way of talking about personality.