While Voice Match learning the sound of your voice sounds like a completely local task, they will force you to keep a history of all your voice commands, searches and activity. Voice activation and match won't even work without that on. Even tho the assistant works just fine if you leave those off.
Not to mention all the rest of these that happen, they even push for these during your first phone activation.
I got my first Android phone this year after taking a very long break from Google phones in 2014, due to getting fed up with how much of a mess Android still was around version 5 and Google's unwillingness to fix the issues so I ended up switching to iOS for years. Now I decided to switch my second phone to an Android purely out of curiosity to see what's been happening to the platform and all these creepy-ass prompts in version 9 don't instil much confidence.