Your opinion is correct, for any crypto transaction to be successful we need the internet.
Unless there will be no survival after the nuclear war, in that way we can say BTC dies together with all of humanity. providing there are survivals there will definitely be a need for the usage of electricity, internet, etc. which makes human life easier and more comfortable then BTC will survive, and there might be a pulse on transactions because of the war shock and the machines which will be destroyed, but as times go on, everything even before the public in fractures and basic amenities can be put to place, BTC transactions will be back to life.