Which one your smartphone?
-apple
-samsung S7
-oneplus
-asus
-acer
-xiaomi
I use a combination of a few of these phones due to their capabilities and features. Apple has some limitations on accepting a few altcoin wallets but the altcoins that are available are implemented to a somewhat secured device. Andriod is not to bad for other coins. I might collect devices for this purpose to having a variety of wallets copied and placed in secure locations offline.