That is true if there is a natural disaster and there is no electricity then you will focus more on how to survive that day rather than to think about your bitcoins. And if wvwr that those thing happen even if no natural disaster there is no way you can access bitcoins because there is no electricity bit if you have charge your phone then you have an internet data in it then you can acess it but I do not think about the connection because of the fact that there are no electricity so  data providers have no electricity too so much better to no transactions that day