It doesn't actually let you settle payments quicker. What it does is set up a "channel" between two participants which can quickly adjust its balance at any time (but only up to the value originally locked in it!), and then ultimately settle out if you want to close the channel.
You can't use it to make a payment to an unrelated person without opening a channel. So there's a "routing layer" where you find a channel in common, like trying to send a UUCP email. e.g. if you wanted to send to another coinbase user, you'd send over your channel to coinbase and they'd send it out again over their channel.
But then .. you could just both use a coinbase payment account?
You can't use it to make a payment to an unrelated person without opening a channel. So there's a "routing layer" where you find a channel in common, like trying to send a UUCP email. e.g. if you wanted to send to another coinbase user, you'd send over your channel to coinbase and they'd send it out again over their channel.
But then .. you could just both use a coinbase payment account?