I bought an air conditioner last year, some wal-mart “smart” AC that was affordable (we had to get three for the new house we moved in to so budget was a big concern) and it has a QR code for the companion app. I finally got around to getting the app this summer and lo and behold, it’s a dead link. Yay.
Even if the link isn't dead, every one of those companion apps will be dead long before the hardware dies because the companies won't pay a developer and the apple developer fee forever.