Well, maybe there will be some validation at the exit of the shop, maybe a message on the phone to check that you indeed bought those things. But cash is going to be gone too in the future-future.
> But cash is going to be gone too in the future-future.
Like famine, poverty, cancer and CSS? ;-)
Yeah, sure.
Seriously though: history shows that if official money is not trusted (for some reason), another form emerges. So no, cash will be there as long as humankind exists.
Maybe, though I doubt it. Cash has some advantages which make it very appealing in certain circumstances. Anonymity is only one of them, and probably not even the most important one – cash does not rely on network being available.
There is a regular war going on in the country neighboring my one, a thing that was hard to think of several years ago. We had a pandemic and lockdowns destabilizing lives of millions of people and thousands of businesses.
What makes you think the US are immune to disasters resulting in having no internet for weeks or longer?