Improvements in search, translation, image recognition and categorization, voice recognition, and text to speech off the top of my head. I'm sure there are a lot more.
[1] https://www.theverge.com/2018/3/27/17167200/google-ai-speech...
Me not.
Maybe indirectly, ads have become more targeted, but we cant be sure how much. It might be just a dtandard small optimization