I think for America it will have to take more time since there is so much paper currency and it will take a while for it to be adopted.
we can end up goind towards a cashless society, but still it would take time to wait for that time. but still cashless society that runs by the crypto would be better as it saves the nature and it is more easy to carry and to use. bitcoin will always be a good thing for todays time, because this time technology is now going boundless. meaning we can do or invent something useful that can help our nature to regenarate. bitcoin can help nature by minimizing the printings of fiats that uses papers.
Well there's that possibility already and you're right, in dubai, they've mostly gone cashless already but to implement that to majority of the world's population, it may take decades or more. Paper money has been in use for such a long time already that for now, it would be unthinkable for aot of people to veer away from using it.