The subtitles have brought so many new things to my attention. Also, the music descriptors are great: "Dark," "Sinister," "Intriguing." Netflix is obviously going to fill any niche it finds available, but I enjoy the current subtitles.
Also, I follow the Santa Barbara Zoo on Instagram (@santabarbarazoo) and they always post an Alt-text for all their posts in the caption -- and they often rival the photos. I guess the point is that, done well, these additional feeds can add value even to those who don't strictly need them. But, for those who do, I'm glad that some content producers take them seriously.