If you don't use a very sophisticated blocking system (for example uBlock Origin in medium mode + pihole) the data is being collected independently of serving ads.

While it will be used for Realtime Bidding and ad-retargeting, the data itself is very valuable in lots of other ways, and even though I am not an expert I fear that in many ways personalized profiles attached to your real world self can already be created and sold to those who want to know more about you.

Even with such a blocking system as described above there will be some data send. So the stricter the User agent, the better for the user. Making fingerprinting more difficult, which is what Safari will do with ITP 2.0, is something that is very important regardless of blocking ads, as first parties want to track you too independent of ads.

- https://github.com/gorhill/uBlock/wiki/Blocking-mode:-medium...

- pi-hole.net

Here are a few reasons.

1. Ad blockers have a performance impact.

2. As blockers don’t have the number of uses that the browsers have, so I have seen websites routinely request to turn them off. However if the protection is built into the browser sites cannot ask users to switch to a different browser, they have to figure something out or suck in less data.

3. It’s also a vote against Chrome and Facebook telling them we really don’t want tracking. Switching away from Chrome is the best way to send a message.

I would say that is the least significant part of the problem with tracking.

For now, that might be the case; however, there are a large number of more insidious uses when that data is sold to/shared with third parties (e.g. insurance companies could use that data to increase your rates or deny insurance depending on your web traffic, employers could make inferences based on your data and deny employment, banks could use the data to deny loans or charge increased rates, etc.).

People should care about tracking because even though Google and Facebook may only care about serving ads, they also have to provide information in response to requests from the government. Any tracking information available to a company is de facto available to the government where the company resides, the government just has to go through the extra step of requesting it.

Chrome sends all the text entered into your 'omnibus' back to HQ. Adblocker isn't going to help in Google wants to track you, and it does.