As far as I can tell, politicians don't spend much if any time thinking about second and third order consequences. GDPR is but one example, but instances of this abound. The default should be to mistrust new laws. Reagan takes lots of flak on the internet, but he was right on the scariest phrase being "I'm from the government, and I'm here to help".
Even worse, this thread is full of armchair lawyers that will confidently tell you there's no need for cookie banners in particular cases. Nevermind that there's hardly any case law about this and each country seems to interpret it differently. Any actual lawyer would tell you to slap it on there to stay protected.