Device-to-device audio communication (think QR codes, but made out of sound) seems very underrated. Much better UX than QR codes or NFC because you don't have to worry about putting your phone in the exactly right place or pointing it in the right direction.

Anyone here with more detailed takes on this?

My understanding is that this was a key feature for early Zoom adoption. 

Pre-covid their video conferencing software was seamless in the office. You’d always share to the correct screen, easily join the current meeting, etc. 

And seems they way they did it was with sound.