Video subtitles and transcription are fairly new in YouTube, and Vimeo hasn't even deployed them as of today.
This means your competition probably haven't added them to their online videos yet.
The reason for that is just an old myth: "subtitles are expensive". "I just have one video and they billed me that much..., I cannot afford making other language versions".
As long as your competition misses this point, you're ahead of them, and your audience will reach you first.
Video subtitles and transcript help improve your search engine position (SEO). Let's recall what happened some years back.
When Google was young, appearing first on SERPs (search engine results pages) was as easy as writing the keyword a few number of times.
Now, it's extremely complex to optimize your SERPs position as to get reached by your audience looking for a specific phrase.
Subtitles now act somewhat similar: Youtube and Google are eager to get inside your videos, and so they'll position your pages far better when you add subtitles.
This won't last forever. When every video has subtitles on it, Google will look for further refinement, as it did before. And YouTube exactly the same (Google owns YT).
The morale is: the sooner you do it, the more you'll get from it, and the more competitive advantage you'll get.