If bitcoin replaced the worlds currency, a lot of people would be screwed as they have no computers
Smartphones
Not needed. Regular prepaid cheapo dumb mobiles will work just fine.
The *end-user* wouldn't need to have the full wallet functionality on his dumb phone, just as long as the carrier does somehow. A
Could this mean that Bitcoin might survive and even thrive in spite of a major global disaster?
Assuming an expansive cellular network is built up rapidly following the event.