I'll be curious to see if Apple gets caught with some surprise or scandal from unexpected behavior in their generative models. I expect that the rollout will be smoother than Bing or Google's first attempts, but I don't think even Apple will prove capable of identifying and mitigating all possible edge cases.
I noticed during the livestream that the re-write feature generated some pretty bad text, with all the hallmarks of gen AI content. That's not a good sign for this feature, especially considering they thought it was good enough to include in the presentation.