Ask HN: Why would Amazon want to track my emotional state?

Amazon just announced a new fitness band called Halo. The most interesting feature is a microphone that listens to your voice and uses AI to guess what your emotional state was throughout the day.

The band will intermittently listen to the tone, pitch, intensity, rhythm, and tempo of your voice and then categorizes them into emotional states like hopeful, elated, hesitant, bored, apologetic, happy, worried, confused, and affectionate.

People usually spend more when they are at either end of the emotional spectrum. They are very happy, why not splurge, they are really upset, why not make themselves feel better by buying something. Many people use spending as a form of self medication, credit card companies and retailers love them for that.

I view it as a predator/prey relationship with Amazon/CC being the predators and I being the prey. Why would I give them more information on my intentions and vulnerabilities then I have too? These companies don't exist to make my life better, they thrive when they extract as much of my money from me as possible, whether to my own benefit or detriment.