In general, yes you can use an old phone as cold wallet. Nothing wrong with that. But is kinda useless. Too much paranoia with air gapping.
A cold wallet you use it ONLY to deposit and check the balance (watch-only), so that scenario with air-gap it doesn't make sense.
Is enough to store the seed in a safe place and use that old phone to restore the seed only in emergency case or for a deposit. It takes few moments to restore it, no big deal.
The thing of keeping an old phone as a hardware wallet is just giving the impression of more security, but in the end is just an impression. Is like wearing a fucking mask. It doesn't serve to protect you.
The best way to protect you, from yourself (your own mistakes) and from other type of attacks, is to use the 3 levels stash: cold, cache, spending. Compartmentalizing your funds for each destination.
In general, yes you can use an old phone as cold wallet. Nothing wrong with that.
But is kinda useless. Too much paranoia with air gapping.
A cold wallet you use it ONLY to deposit and check the balance (watch-only), so that scenario with air-gap it doesn't make sense.
Is enough to store the seed in a safe place and use that old phone to restore the seed only in emergency case or for a deposit. It takes few moments to restore it, no big deal.
The thing of keeping an old phone as a hardware wallet is just giving the impression of more security, but in the end is just an impression. Is like wearing a fucking mask. It doesn't serve to protect you.
The best way to protect you, from yourself (your own mistakes) and from other type of attacks, is to use the 3 levels stash: cold, cache, spending. Compartmentalizing your funds for each destination.