They are used a lot with Bitcoin, whatsapp uses them for pairing with the web interface, authenticator uses them to import keys. I think they're great. They're

They are used a lot with Bitcoin, whatsapp uses them for pairing with the web interface, authenticator uses them to import keys. I think they're great. They're very fault tolerant and can contain a ton of information. It's a great way to scan stuff from you computer (or anywhere else) and import it into your phone.