The WWDC keynote is mostly about new shiny stuff to tell people all the cool stuff coming to their phone and why they may want to buy a better one (Apple Intelligence this year).
As you pointed out it’s not new information. And “doesn’t suck as much” is not exactly high marketing copy. They put it on one of their slides of random features coming to the new OS so people would know it’s there but didn’t spend any time on it.
I agree with you, they weren’t trying to hide it. It just wasn’t that interesting compared to everything else they were doing that no one knew about (outside of perhaps the rumor mill).