It’s very helpful that the QR code is included on the box, on the switch, and that there’s an extra sticker. Now I’ve finished setting up my switches I plan to ditch the boxes but should I keep the QR code stickers? I don’t plan on moving for a few years at least so thinking about what situations this could be helpful for.
I guess I could stick them all on a piece of paper and label them. Any other ideas?
I think if you ever have to factory reset and repair the devices that you’ll need the barcode. To avoid having to take the faceplate off the switch to get to the barcode, I’d put all the barcode stickers on a sheet of paper and label which barcode is for which switch. Then hopefully you’ll remember where you stuck that piece of paper if you ever have to reset and repair. 
If you don’t want to keep a hard copy, just take a picture of it and store that.
I don’t have any Matter devices, but that’s what I do for all of my S2/LR z-wave device codes. If I need to re-pair any of those, I can just pull the code up on my laptop and scan it with my phone - works like a champ.