Punish bad pop-ups, so people are wary of them ('wait is this bad') and discover (and find attractive) the possibility of not having one (can't be fined for a bad thing that doesn't exist) & network effects ('wait how do they have no pop-up')?
It's not about cookies. The legislation and the consent popups are not about cookies. They're not even about whether they're essential.
The banners are there for you to opt-in to your activity on the website and beyond to be tracked by a 3rd party, possibly across multiple other websites.
We do not need to discuss whether a cookie is essential, because it's a red herring. It's not about cookies, it's about behavioural tracking, it's about your browser activity being sent to 3rd parties, being collated and used to e.g. serve you advertisements to sell you shit.
That's what I'm saying. I recognise that's not what the law was intended to do.
The problem is that individuals and small businesses would rather interpret the law in a way that isn't going to get them in trouble, even if it is over-reaching. There has been a level of paranoia stirred up, caused by other companies interpreting the law badly.
It's like staying away from all bodies of water because someone sometime drowned while swimming in the sea. It's a vast overreaction, but it works.
In short, we have lots of armchair lawyers giving idiot-in-a-hurry interpretations, and everyone is doing it wrong because everyone is scared of doing it wrong.
It doesn't matter what the banners were intended for.
It's not that simple though. Even though I agree with you that it is not JUST about cookies, the legislation and guidelines do go into some cookie specific details such as when you can use session cookies vs. long lived cookies as an example.