If the connect with friend interface also had a QR code for app download and could trigger a connection between our accounts upon download, that would remove enough friction that I could start recommending this to my friends on the fly.
I'd have a hard time getting over my aversion to this. I automatically reject any app's attempt to find local devices, etc.
Camera, and point it at their changing screen (or both at the same scene at the same moment). Not too intrusive.
GPS, but that would require location permission. Intrusive.
Audio, but that would require allowing microphone. Intrusive.
We tested it one time with like 10 phones and everyone bumping each other / the wall as a control, in the same room and it nailed every actual pairing and ignored the others. The wiki has more, but lacks the subjective experience of how magic it was.