Tracking in client-side software that occurs to make money is typically described in privacy policies, and a browser adding additional tracking would likely cause an uproar. While Firefox may provide a better default regarding sync, there is a difference between saying "stop using Chrome" and "enable client-side encryption".
> Tracking in client-side software that occurs to make money is typically described in privacy policies, and a browser adding additional tracking would likely cause an uproar
Emphasis mine. Yes, you might trust them not to track you, or to trust that someone will find out if they do, and that you will hear about it if so. But far better would be to use an open source browser (either Firefox or Chromium).
