absolutely bitcoin can only be used on electronic transactions, because bitcoin itself does not have a physical form such as now exist currency, bitcoin only convenient means used for electronic transactions,
electronic transactions have requirements include: must have internet connection, must have a PC or notebook, if all the above requirements are met, the use of new bitcoin can comfortably ...
Most fiat transactions are done electronically now. The world becomes more connected through the internet everyday. I don't see this being an issue unless there's a massive power outage, but at that point we will have much bigger problems on our hands.
if there is a massive power outage, then you must have a very large generator sets, so that your electronic transactions will not be disturbed, you can connect to the internet at any time without being interrupted by outages uncharged, but of course requires a generator set fuel source not a little, and even this requires a lot of cost.