More and more people are using smartphones thanks to budget friendly mid-rangers, almost anyone can now afford to buy a smartphone.
Mobile payment is becoming more common and it is an opportunity to acquaint people more into using bitcoin . Mobile payment will eventually replace credit cards or at least will make them less mainstream. An example of this is Apple Pay. Bitcoin smartphone wallet apps are to use when you have a transaction, you just scan a qr code and the transaction is done though will take some time to be confirmed.
Smartphones as you said, are becoming more like a one of the common goods, most of people have bought it because they are not so expensive nowadays.
But people may use also just regular wallets like blockchain.info or other web wallets, you can login on them through browser at mobile.
Not really! many people keep their bitcoin in their smart phones, me the one of them because you will feel safe and can check it every time you want to see and have other benefit like you can see avarange price so you when must sell bitcoin atto exchanger.