In my eyes anyone wearing one of these is a pervert. I simply don't see who else could be the audience for a purposefully discreet camera built into a pair of glasses. Even Google's attempt at glasses were more overt that these. I'd say Meta is shameful, but that's not exactly a shocker to anyone at this point.
Edit: Seen a few suggestions, but my counterpoint to all of them is - you don't need the camera to discreet fir any of these purposes. You'd only need it to be discreet if you didn't want people to realise you were filming, which just seems aimed towards perverts in my mind.