Finch is mainly used for A/B testing. It doesn't push actual updates, all it does it turn existing features (flags) on and off. It's used for quickly A/B testing or incremental rolling new features and is designed to be more agile.
> not wanting to be tracked
here's a hint: ad impression for unknown user is 0.01$ and for logged in user 2$. guess why Google has a browser now...
if you have a logged-off cookie, and the publisher can associate you with a logged-in user at a near point in time, they can charge you as logged in impression.
It should be entertaining when car makers use the same strategy: "Oh yeah, we have this system where everytime you turn the ignition, your car polls us and updates its assistant, motor, steering and airbag settings. Don't worry though, we mostly just use it for randomized tests and field trials."