He sighs. Deeply. Because he absolutely agrees with Iroh.

"Uncle, just look. That's called a video. It captures a moment. It's incredible. It's not even magic, it's— I mean, it is, but it's technology, other worlds have this, too! It's like a moving portrait with sound, but real, like time can be put in a jar and kept away! Imagine even freezing a whole play! They use videos to make plays that are called movies, too."

Okay, Zuko, get off the metaphors. He's very enthusiastic about movies and videos, even if he is not wont to use video messages himself often to communicate; he's too self-conscious of his scar to default to that online. And likes the ability to say what he wants over text with more time to consider his words, a rare luxury in life Zuko needs more than most others do. But the novelty of film itself — especially not even knowing about film, just about its descendants in modern movie magic technology — is mind-blowing forever, and deserves attention.