They already had the "neural engine" as part of their chips, but as for the whole "AI" thing it as much noise as it is value. This is to the point that there are products I will actively avoid if it has "AI" on it. For me this is like a dishwasher that needs an app for some of its functionality, rather than solving a real problem.
There are certainly cases where AI or AI-like can be useful, and there is no question that Siri hasn't had the iterative improvement that it needs to feel like it is improving and keeping people excited. Its just that AI is just another tool and it shouldn't just be jammed into everything, just to satisfy marketing or the devs who don't want to think of how properly formulate an algorithm,
BTW this is not intended as a defence for Apple, but the problem of trying to make AI the magic sauce that will solve everything, while actually causing more noise, and CPU usage, in a good number of cases.