You did not mention the Lightning Network, where fees are negligible. You cannot seriously research on bitcoin without coming across the Lightning Network.
Off-chain solutions to the inherent inefficiencies of blockchain applications also sidestep the advantages that cryptocurrency proponents promise blockchains will bring.
Not really. Lightning is build on top of Bitcoin, every Lightning payment is a real Bitcoin transaction that can be settled to the network if necessary. It has all of the benefits of Bitcoin, plus higher throughput, enhanced privacy, lower fees, and faster settlement.
