Recently, Jason Kottke summarised a Twitter thread about why people who can hear normally and also understand the language use closed captions when watching video content.
Turns out many of you watch TV this way for all kinds of different reasons — to follow complex dialog in foreign or otherwise difficult accents, some folks better retain information while reading, keeping the sound down so as not to wake sleeping children in tight living spaces, […]
I also watch as much as possible on Netflix or on my tablet in general using subtitles simply because it helps me to understand names better. I’m very bad with names and even more so when I only hear them. Reading or especially writing a name does something with my memory that marks it as more relevant for me which makes remembering them easier. Subtitles therefore help me untangle dialogues where people talk about other people. Without them I’d either have to rewatch many exchanges or to reconstruct them later on.
That being said, I’m also someone who prefers watching videos with headphones. While we have a good audio setup for the big TV, if I watch things on my own (even when I’m alone) I prefer the sound isolation of my headphones. No matter how loud explosions are, I don’t even have to think of this might disturb someone else. Therefore, I only use closed captions in addition to the audio track of a video but not as a replacement.
Nevertheless, closed captions are simply a great example of a feature that was originally aimed at a specific user group but then turned out to be useful to pretty much everyone but not all the time. Watching videos without them would be far less enjoyable for me!