On the other hand, signing involves actual translation, not just transcription, which is much more likely to drop meaning or introduce confusion. Translation is already hard enough, and live translation is a whole other level of difficulty.
Now, you’re getting the inflection of the interpreter and not the speaker (derivative). Certainly you’re not hearing inflection on the original orator, either, so maybe it’s a mixed bag.
Subtitles in general, and live captioning especially, avoid editorializing or taking creative license- they're literal translations of words without other cues added in.
One nice exception to this has been the community subtitling work involved in various Taskmaster spinoff series, where explanations for cultural jokes or idioms are added into the subtitles for foreign audiences, especially when the joke is a pun or relies on a mispronounced word to make sense.
Live subtitling (on the BBC at least) is mainly done using re-speaking and voice recognition, rather than typing.
Interesting side note: if ever subtitles are turned off, or we are watching TV elsewhere, me and my wife can't 'hear' well. Even if the volume is up. Like we've untrained our ability...
It's way worse than even using a cheap computer with open source solutions - it's strange no one at the BBC decides to resolve this as it would be easy and could easily give the public a far better result. Even if you took a hit on the most obscure words, off the shelf would outperform the current process by a country mile.
Anyway my theory is that sign language interpreters may be much better at this because sign language uses the same areas of the brain as speaking[1] so they're able to listen and sign much more intuitively than typing. Think if you were able to listen and speak at the same time without your "speech" drowning out what you are listening to.
[1] https://maxplanckneuroscience.org/language-is-more-than-spea...