physical money is can be use offline while bitcoin dont,so it only means that all of the
transaction can be made by physical money but virtual money like bitcoin cant.
And using bitcoin by everyone is another issue.although its almost impossible too because
many countries dont wany bitcoin or the cruptocurrencies enter their country
Probably bitcoin will not destroy fiat system but gold will do that. We need offline money but paper money is no more appropriate for this century, fiat money system is not so fair, sometimes it harms some countries. We will back to use gold, one more time, and for the last time. But I don't think bitcoin will be used by almost people in the world, because its price will be very expensive and its fees as well. Except there are people who can manage bitcoin transactions and make sure that the fee will keep low although it's price is very expensive.