For loading two-factor authentication secrets. Or anything else you can think of that has too much information to convey with a short link. If you are directing people to a web site using QR codes then you're doing it wrong. Well, wrong now that everyone has realized just how limited QR codes are.

I do for any printed media. It makes it easier for people to look up the corresponding electronic version of a document. QR code has its uses, but tends fail when misused. QR code is best when interacting with it is strictly optional.

They ever did?

Well I think people did, once, but then immediately discovered it wasn't worth the effort.

They're great for managing parts in a manufacturer's storeroom. A QR code is more information-dense than a barcode.

I use them at bus stops to pull up live tracking