Audio mixing being shit as mentioned by other commenter, but also i don't want ny neighbors to hear everything i'm watching by cranking the volume up just so i dont miss dialogues.

I seldom use them while watching YouTube on my own. But my parents use them all the time. And I always went for them on the TV in their place. Because with the TV in the living room, and often a lot of ambient noise and interruptions, it is way easier to follow stuff when the subtitles are going. Also, my parents tend to watch a lot of British TV. We've got a lot of experience decoding strong regional accents, but the subtitles reduce the cognitive load.

Quite simply the audio mixing for TV and movies is utter shit. You shouldn't need a 7.3 sound system to potentially hear the actors legibly. The stereo speakers built into my TV should be adequately supported, and it is frankly the default set up for most people including myself.