It enhances the ability to fingerprint me, effectively exposing my browsing history.
If Google offered it as an "opt in", giving me some reward for sharing my personal information that Google sells to advertisers, then that is a fair deal. In return for some form of sharing the revenue, Google gets to sell my information.
But that's not the model. It's still the "you're a product" model where Google not only gets to sell my search history, but now also continues to sell my browsing history.
I can see how it benefits Google and how it gives them/you something to sell to advertisers, but what's in it for me?
What you get in return is that ad-supported sites you visit are better funded because they can show better-targeted advertising.