the question is "why".
when you can use a much easier way of using a live linux (without the hassle of a cell phone and its privacy hazard of constantly being connected to the network and even possibly broadcasting data to your network provider) and print the safest cold storage meaning on a paper, why would you choose to use your cell phone?
Because its portable. no funded BTC cold storage is on it, thats on an external sd card, (easy to stash away), this is only a portable qr address; reader, generator, and transfer system. I have used linux usb and i always had to find a computer to generate addresses. This lets me do it whenever, wherever, and securely on the fly. A linux usb and trezor didn't offer me that. I often sit on a bench in a park or in my car at lunch and generate addresses offline in minutes. I always have it on me as I carry it around with me it always has only one BTC address and keys with around $20 on it (for a beer or quick trade). And other than that all it has is a few blank generated public qr addresses waiting for putting funds onto it, As I have the blank copies at home as well with the private key in cold storage this is no problem, It is more portable than my linux usb, and as a bonus, this totally offline device has a screen for displaying QR and a camera to take a pic of another QR and save it to file.