It won't happen.
Smartphone for bitcoin mining? you are just destroying your phone.
Smartphone as digital wallet, you can simply download an app / wallet and that's how you make it as your wallet.
Everything is possible through our technology, who knew on 2009 that bitcoin will be as it is now ? Who knew that microchips will be used on curing such diseases and illnesses?
Are you aware of what smartphone are capable of ? Almost everything now can be done with the help of mobile phones. Who will know what the future is with smartphone as our technology advancements continue to amaze us.