Performance is a given, loading less = faster. Same with security, its just a few bad actors who keep allowing 3rd party content and malware. Many networks dont allow for anything other than text + images which have no malware possibilities.

Those two issues are starting to be solved by this consumer backlash and its a good thing. However when it comes to privacy I never understand how people think paying for things with their credit card is somehow more private (especially with all these data breaches) than some random ad network tracking script. The 3rd party cookie was actually a great thing that could easily be deleted and also stored any opt-out settings for users who wanted to skip tracking. Now with random out-of-context "privacy" reasons, browsers have ruined the effectiveness of cookies which means most networks cant even store a proper opt-out preference and they're also resorting to fingerprinting and other signals (at the ISP level) to track users no matter what device/platform/browser.

What the industry needed was more regulation and better standards, not this brute force guerilla warfare which is really harming the entire industry and leading to an eventually smaller and "closed" web.