The only OpenAI integration is giving users the opportunity to have their model answer questions. No Apple services, and no general queries rely on OpenAI.
Yeah, the OpenAI integration they demonstrated at WWDC showed a very prominent “do you want to send this question to ChatGPT?” dialog when it kicked in. The email feature absolutely isn’t using OpenAI - plus the OpenAI integration isn’t in the iOS 18.1 beta yet.
In any case, dealing with spam/phishing is always an arms race.
One of the drawbacks of AI, is that I suspect it will have patterns that could be figured out, and folks will learn that (crooks tend to be a lot smarter than most folks seem to think. I'll lay odds that every hacker has an HN account).