(following this tangent) My impression of QR's problem was:

1) High ergonomics barrier; the user needed to install a QR app from the appstore or find the icon for it and start it.

2) People who are not on HN don't know what it is anyway.

Now that it's built in to most Android/iPhone cameras, #1 is solved. Now that #1 is solved, #2 is self-solving.

QR gets a lot of jank but when I use it, it's very handy.

Probably more accurate an analogy than you think:

https://picturesofpeoplescanningqrcodes.tumblr.com/

Not of cuecat literally; the failure of cuecat in 2019.