Phones can break very easily (this is especially true of their screens). If a phone's screen was to become cracked to the point that a QR code is not readable then what would happen? I see that you say it is easily clone-able but did not see additional information in the first few posts.
It also looks like the cold storage phone is not actually disconnected from the internet
Bither Cold Wallet
-snip-
3. Realtime monitoring the network status (Wifi, 3G, BlueTooth).
If a computer/phone is connected to wifi to monitor the network then it is not truly offline. I don't see any reason why the cold storage couldn't push the TX from cold storage (or why it is even considered cold storage)
Mobile phone is definitely stable than a computer, when you keep the phone in your home
Monitoring network status does not mean to connect to the internet. It will just monitor the phone's setting, when you try to open the wifi, 3G, BlooTooth, Bither will warning you.