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.
Bitcoin wallet on smartphone make users to do some transactions easier without need to access wallet from a personal computer.
There are some bitcoin wallets for smartphone and I use one too for daily transaction and these platform contribute for bitcoin expansion.
But, spending bitcoin from smartphone cannot compare to others platform such as Apple Pay which doesn't need to pay fee transaction and wait for some time to be confirmed, it has different path for now as long as we have block size issue.