I agree in general, but when I see a dialog box titled "We respect your privacy" and a choice between "allow all" or "see more", I donate 0.10 € to NOYB.
If anything, every time I have to click through one of those banners I wish that activist organisations/politicians had to pay me for having to go through it.
> In most cases, the add-on just blocks or hides cookie related pop-ups. When it's needed for the website to work properly, it will automatically accept the cookie policy for you (sometimes it will accept all and sometimes only necessary cookie categories, depending on what's easier to do).
You can disable cookies in browsers so that cookies do not persist after session close. Firefox lets you add a whitelist of sites to allow cookies, too.
If I understand the law correctly, your suggestion is good on practice but could be harmful on the long run.
When I click "I agree" I am not agreeing to cookies but rather to tracking. If the website wants to track me with (say) browser fingerprinting, deleting the cookies will not stop them from tracking me across sessions. Even worse: since I agreed they no longer need to show me a warning, so I may not even notice that I may want to revoke that consent.
If I don't want to be tracked, saying "I do not consent" is the only legally-actionable way. Deleting cookies works now because cookies are still cost-effective, but this won't remain true forever.
I wish that was true, but those extensions are far from flawless. Still, they are a massive improvement over having to click away all banners, especially for those of us who have our browsers set to clear cookies when quitting the browser.