If you add this to the model that guesses identity based on the sound produced by inputs (keyboard , mouse...) you basically end up with an "ambiant sound fingerprinting" tech , where the sounds emitted nearby a device can be used to accurately determine the individual that's standing close to it...
If you add this to china's facial recognition , it scares me to think how "Gattaguesque" our societies are turning thanks to Machine Learning and Big Data...
This research stops short of tying speech to any individual's appearance. It isn't even an advancement toward that goal, which it explicitly doesn't have.
The facial identity part seems little more than an average/example visualization of traits (age, gender, etc), which can be inferred from speech data with some accuracy (as we've always attempted in the form of mental models in our brains).
Not trying to be contrarian, genuinely wondering why I'm not among the concerned, and if I'm missing something.