Yes, they are extremely useful if you actually need to pull data off a physical object. We use them at all of our conferences to scan badges. I embedded a reader into a web page, so my coworkers can just open a web page on their tablets, and they have a fully working system that can scan a QR code from a badge to log attendance at sessions, or assist people on the fly, without having to send people over to the registration desks for help with scheduling or other questions.
That is just one use - but anywhere that you see a barcode, a QR code would serve the same purpose. Really, that is all a QR code is - a fancier barcode.
You may be thinking of the marketing gimmicks where when you scan a code, an embedded URL is opened. That use case does feel gimmickky. But that is not their most practical use.
Well, it kinda does show that you've never used QR codes, otherwise you'd know that all of this is pretty much handled by the app. Which means:
No need to store the hi-res pictures of bar codes; no need to load up camera ap, as that's handled by the QR code app; no need to load up the browser, since a small embedded one appears to open the link, as a rule.
That said, yeah, it's 100% a gimmick. I have only seen one or two problems for which QR codes really made sense, and none of them included scanning a URL with your phone.
In Hungary the train company sells home printable tickets and they use QR code to ID it. I think it's weirdly encoded, maybe even encrypted somehow. You don't have to print it though, you can just open it in your phone than the ticket control scans it with their own phone and in-house app.
As for personal use, I don't really know. Storing your larger bitcoin wallet on paper could be reasonable.
WeChat (A very popular communication app, ~550 million active users) uses QR codes as a way to add contacts. The app will display a QR code and people you have just met can scan the code to send a friend request. People use this feature quite a bit. It saves time over ensuring that the other party is typing your name correctly.
QR codes are things that techies think non-techies actually use. "Grandpa doesn't want to type in some URL, he just wants to scan an image and be taken there!" Then marketing gets involved asking for the QR code that the techies told them "everyone uses" and its now a requirement on all posters and advertising materials. Now here we are.
Filling up your phone with a bunch of hi-res pictures of bar codes, not to mention having to load: 1. QR code app 2. camera app 3. browser app
These things are 100% in the gimmick column in my life.