As for the glorified chatbot is of course one of the applications of AI, but i refuse to believe it has a very complex model, and the computational power required to use the model is also modest enough that most smartphones can execute it without any noticeable impact on battery life.
On the smaller scale, most of Apple's AI stuff is running on-device[4]. From iOS 15 all of Siri's "voice to text" happens on-device as well. While it's probably still a glorified chatbot, i for one enjoy being able to enter "pet autumn 2019" into my photo search bar, and be shown pictures of pets taking during autumn 2019, regardless of location.
[1]: https://engineering.berkeley.edu/news/2021/08/using-machine-...
[2]: https://medium.com/mlearning-ai/machine-learning-in-fraud-de...
[3]: https://www.sciencedirect.com/science/article/pii/S026840121...