It is doubtful that even in the long-term future everyone is going to have internet on their smartphone.
Credit cards can work on either a phone line or internet, so it would be ubiquitous as opposed to bitcoin which cannot work on a phone line?
One hundred years at the beginning of the last century ago nobody was able to purchase an airline ticket, watch a tv show, use a credit card, make a mobile phone conversation or use the internet.
That doubt of yours reminds me of people arguing a man can't fly.
As for the second thing.
Do you know how credit cards work over a phone line?
You still must have a dedicated phone line! which in 99% of cases is costlier that internet access.
Besides, the technology behind the dial-up used for credit card process is so simple it can easily be adapted for bitcoin tx.