> don't we get that from long-running TV series, audiobooks, visual novels, videogames, manga?

Different media affect and engage us in different ways/modes, and reading is a process that requires a particular set of skills that is different vs watching TV.

Much like listening to music with one's eyes closed vs reading the notation – one might get a sense of the composer's intent, structure, theme, emotion, etc. from both, but there are major qualitative differences in the two media.