It depends. For me, I make marketing videos, so marketers across the world who don't speak great English and can't understand my fast pace of speaking can read the captions.
It has helped me reach wider audiences. Plus I use the captions for social media sharing. most social media users don't have sound enabled, so captions are a good way for people to watch your content without sound on, especially in public or at work where sound enabled wouldn't be acceptable.
In terms of the YT algorithm, I haven't seen any evidence of it helping in that respect.
Hope that helps!
