I agree with the others. Just to give an example . . . I recently watched the entire movie 1917, a two hour movie on a plane. I can never hear well on a plane anyway, so I just watched it with no sound. I'm sure I missed some details, but I feel like I understood the story and everything that was going on perfectly, because the visual information was enough.

The phrase "film is very visual" means that movies and TV shows rely heavily on images, actions, and visual effects to convey meaning and tell stories. In other words, much of the information in films is communicated through what we see (e.g., facial expressions, body language, scenery) rather than through spoken language alone. So, while watching films can help with understanding spoken English, it's possible to follow the plot and understand much of what’s happening even if you don’t fully understand the dialogue. Because film is so reliant on visuals, learners might not always be practicing listening or language skills as much as they think when watching TV or movies.

It depends on the film. Of course Fast & Furious is very visual. But watch a more philosophic movie like Godfather or Knocking or Knockin' on Heaven's Door. Those movies are more about the dialogs. And obviously it shouldn't be the only way to learn the language. It should rather be a supplement.

It means, what you see with your eyes (with your vision) is a big part of the experience, when consuming movies / films / video footage. Of course there is sound (audio) also, but sight (the visual aspect) is a big part of it. If you are listening to the radio or an audio-only podcast instead, then you need to focus more on listening to the sound and understanding the words, in order to understand what's happening.