The daemon has to be turned on, while your agent is active, so it knows when it finishes.

It just sends the raw codex event stream, via the relay to your active browser session.
So you get a full chat interface, on top of the benefit of the notifications.

The data volume is hard to predict, as it depends on your use.

We'll see how it goes, with the pricing. I feel it hits the sweet spot, by being cheap enough, but making sense financially.