Add transactions through radio or a independent wireless mesh network that doesnt need an internet provider. I think those kinds of transactions would be the most important because they cant be censored by anyone in power.
In the end there is a party that broadcasts the transaction to the network through the internet, so it's not entirely bullet proof. I have yet to come across something that's truly censorship resistant. That however doesn't mean these semi offline networks aren't useful. I have seen a demonstration where its usefulness peaks in areas hit by natural disasters and whatnot.
What I am looking forward to is the day that a wide range of compatible hardware wallets will allow you to swap preloaded private keys in a direct peer to peer manner. Benefit here is that no one externally will notice that coins have been put to work because nothing happens on-chain, while in reality the coins may have had hundreds of different holders already. I don't think we're that far away from seeing this become reality.
Its useful when the entire world is hit by the big one. The greatest financial collapse of all financial collapse, World War III or an alien invasion lol. We will need low energy, portable miners and nodes thats connected on a radio or wifi mesh network.
Its going to be the most important transactions in our lives thats done by blockchain.