Then I don't see "yes" as being opinionated or biased. I'm assuming "OK" was needed because "yes" is otherwise used in so many contexts, including just as a no

Then I don't see "yes" as being opinionated or biased. I'm assuming "OK" was needed because "yes" is otherwise used in so many contexts, including just as a nod to keep a conversation going, in no small part because of its neutrality. So a new word allows for more intentionality (which is important, and we still agree fills a really big gap)