* data density (up to 100 times more than barcodes)

* built in error correction (partially marred qr codes can still be used)

* skinable\customizable (embed your logo, change colors, etc )

* 360 degree scanning capability

Barcodes still have their place but the QR code does have some unique properties

The confusing thing about this question is that "other similar methods" includes QR codes [1] -- they're just a generalization of 1-dimensional bar codes to a 2-dimensional matrix, with some error correction and alignment information to make scanning them theoretically more reliable.

They also have native support for some data types, like URLs. Other than that, it's mostly that they have some traction.

[1] https://en.wikipedia.org/wiki/Barcode#Matrix_.282D.29_barcod...

The amount of information they can hold is especially important in the case of bank transactions. Alipay and Wechat Pay (in China) have QR codes that change every minute. The merchant transaction has to be performed with the current QR code. It's basically a poor man's substitute for the encrypted handshake provided by contactless payment protocols. If someone got your payment QR code they could only abuse it for 1 minute.

I do dislike the use of QR codes for static data, such as a username on business cards and posters. From a design standpoint it looks horrible and busy. I wish those apps had the ability to recognize a logo instead. Or even just a UI to scan and OCR a text username on a business card.

QR codes are much more information-dense than 1D barcodes. Try encoding a string like "The quick brown fox jumps over the lazy dog" (43 ASCII characters) using these tools and seeing how much space they take up:

* https://www.nayuki.io/page/1d-barcode-generator-javascript

* https://www.nayuki.io/page/qr-code-generator-library

I'm assuming the largest advantage is just the amount of data they can hold. One of the top google results[1] indicates that 1d bar codes can hold ~100 characters, while 2d ones can hold ~2000 characters.

There is also a bit of artistic freedom you can do with the 2d ones. They really aren't as ugly as the 1d ones. Especially if you use them to "frame" something. Note, still not pretty, per se. Just not as ugly.

[1] http://support.idautomation.com/Barcode-Learning/How-much-da...

It can store various data formats, eg. vcard. You scan it and save every phone number, email, etc immediately. Or WiFi credetials, including both the network and the password: scan, tick, connected.

1. Denser (ie, more information per unit area)

2. More redundant (ie, more surface area can be destroyed and still be able to recover the original message)