I haven't downvoted you, but I'm a bit troubled by your unbridled enthusiasm for how amazing previously futuristic technology is without any consideration of the ways in which it can be abused - as historically such knowledge about others has been abused. I invite you to consider the experience of people whose appearance is distinctive enough that complete strangers feel emboldened to just casually attack them in the street without any prior provocation.

Now imagine the ramifications of having an app that can reliably tag people as gay or suchlike. How do you think that's likely to get used in the real world?