Well it is simply that cash really works offline
There are no serious boundaries to have a transaction between two bitcoin applications offline. By a bluetooth or such. Those applications would have to have some kind of a lockdown on those "transacted" bitcoins. Once the internet connection would be established the transaction should automaticly reach the blockchain to proceed further. Ofcourse there could be some exploits to this. But cash can be falsified as well.
and it is the traditional way. This is the way of trading where we became dependent to it. Having a cash in real life is the traditional way of living, means that every people used that especially our elders. But bitcoin is the new money or new currency. But I think we need to cope in the future. And this is the future, this is bitcoin. The next generation of currency
Prior to that, there were traditions to pay in a gold backed currency and prior to that, with actual gold coins. Traditions change, faster than you think. It isn't any boundary. What is a boundary is a force. This force is the force of the guns of the government, that enforce the laws and regulations.