I don't like to have the thought of smartphones being the most important thing about Bitcoin Transactions because almost everyone that has an active Internet connection would have the opportunity to build a Bitcoin Wallet and do transactions in real-time. Since the whole process of building a Bitcoin Wallet only consists of about 5 minutes of the person's time, the person has the option to receive money without the need of a smartphone -he could just have a print out of the Wallet information and the money will get transferred to it by the sender.
Times have changed, if you don't have a smartphone, you don't exist.
If people using smartphones wouldn't be able to use bitcoins you could just surrender the flag now and be done with it.
Fortunately enough there are a lot of apps and common uses.
Time is money and doing things while you wait for a bus or on the metro is a big advantage.
Those 5 minutes you talk about are a big turn off for a lot of people these days.
Yes, a smartphone can greatly simplify and speed up all operations when you are on the road. It is very convenient.