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.
Just because we have planes does everyone use them daily? No, they aren't always suitable and there are barriers to access (cost, distance to airport). There are limits to how far cryptocurrency can reach, its defined by limits of presence of internet infrastructure and reliable access. Might not be a concern to you but globally its an issue.