A QR code is just a bit of text encoded in an easy-to-read scheme (for machines). It lets you link to the app download page on the App Store / Play Store. QR codes cannot run arbitrary code on your phone.

They're obviously talking about the app the QR code points to. The one you suggest should be a requirement for ordering.

Apps can, though.

Convenience.

Order food on my phone and they walk it out to my car while I'm listening to ads on the radio. Win, win for everyone.

And I have the McD's app so locked down I'm surprised they actually let me order food.

But is it convenient? Really? I've tried this stuff and it's been without exception a subpar and slow experience. I can see how it could be a great experience, it's just that it's always contracted out, framework upon framework shovelware. ad infested if you're lucky.

The only upside I can find, and it correlates with what crowd is positive, that it suits those that really want to avoid human interaction.