Yes you missed something: He talked about L2, which is a general term for "layer 2" networks that work on top of the blockchain.

For example for Bitcoin there's the Lightning network as L2, where you do one transaction to open the channel, and one to close it, and channels can remain open for months. Payments are routed through a network of channels, so you only need one or a few channels to other nodes and can reach all nodes in the network.

The transactions are much cheaper in this network precisely because they're not on chain, but it's still secure because each L2 transaction leads to a signed (but not published) blockchain transaction that each party of the channel can choose to publish at any time (and close the channel).

There's a bit more to it, and I recommend anyone who isn't aware of L2 networks to look into it.