ChatGPT alone is among the most popular apps ever made, and it's available both inside and outside Apple's walled garden. Letting it reach audience in countries where Apple doesn't have much of a foothold.
I do wonder if new Siri is any good though. Apple used to be a genuine AI leader, but they totally sleepwalked through LLM revolution, and Siri's response quality was a sad joke for a while now. Did they bring it up to modern standard?