When we did this at work, I at first shrugged.
La di da.
But my ISTP neighbor in the cube adjacent was so fascinated. She talked about it for days, asking every person who came to see her what their type was. She even took her assessment in when she went for her quarterly meeting with the boss. Her fascination got me more interested.
So I ran the numbers on my SO. He is an ISTP like my cube neighbor, not what I thought what he would be. (I most certainly thought he would have the NF core like I do.) And when she said, "I don't let me feelings govern me; logic tells me what I should feel," I became even more interested. What a foreign concept! But I certainly recognized what she was saying because it sounded so much like him.
I dunno.
It's interesting because it gives me a framework to help me to understand why I seem to see and feel things differently. What a relief - it's science.
Ok, I'm off to google ennigram. (Wondered to what you were alluding previously, Fitz!)