I had Smart Features enabled for years. Years! They worked okay. They put good accurate stuff on my calendar and so there was useful work being done by the AI in background.
Unfortunately, in the past few months, Gemini AI really started shoving its way in. And there were some features that were really unpalatable, that were basically dealbreakers for this. Yeah, I believe the "AI Summaries" had a lot to do with it. They were bad, misleading, and I did not want them crowding up my app.
I couldn't disable those features without disabling Smart Features entirely. So that's what I did.
So now I sort of suffer without the automatic email event-calendar integrations, and the other cool stuff that AI had provided, but it's totally usable. I have no trouble using it as an email service with that AI disabled. It works fine.
Anyway, it is no secret that Google has always used the text of our emails for their own marketing and analysis purposes. Always has. Why did you think Gmail was a free service? Obviously, you were paying for it! We all paid for it with our email content!