Generally, when a visitor visits a website, which I call an interaction, then they must agree to its terms of service. This forms a contractual relationship. Contracts are private, and outside of things like not promising to do something illegal, it is up to each party to decide on its terms. In this case the website generally decides on the terms, and then the visitor opts into them through use of the website. Much of the issue lies within contract formation. When a lawsuit happens later, one thing that is frequently questioned is whether the contract is valid. A common angle is to claim the the contract is invalid because it was not correctly formed. Bad contract formation. For example, in a different setting, you didn't sign your name on the dotted line when buying a house or something like that, so there was never a contractual agreement, so there was never an actual sale, etc.

However, there is case law (law made by judges who hear cases and issue opinions) that says that sometimes contracts can be implicitly formed. For example, if you as a website visitor are given proper notice of a website's terms of use, and then you continue to the use website, you have implicitly agreed to the terms of the use. Even if you didn't sign anything, or check any box somewhere saying you agree. No explicit action has to take place.

Except, that is not exactly worldwide statutory law (laws passed by government and written down in the books with codes like Law #1234.56). While the issue of formation is mostly settled, there is still some room for creative legal maneuvering. Aka lawyering the shit of things. Aka screwing things up because someone with deep pockets is paying you to win using any angle you can get.

This cookies notice and agreement probably falls right into this category. And while it is generally settled law that the contract is formed even without this agreement, some schmuck somewhere still thinks there is wiggle room, but it is merely case law and not exactly authoritative, especially not in the international setting.

When in doubt, lawyers adhere to CYA. Cover your ass. Use the narrowest, most conservative, safest interpretation of the law. In this case, there is this tiny bit of doubt, so CYA. Just in case.

I personally believe you can make a good argument that contract is implicitly formed merely from continued use, and the notion of requiring express consent is outdated. The law is catching up to how things are done online, the trend is rather obvious, and anyone whining about it is probably just some established cash cow business that somehow wants to manipulate the market to further extend its antiquated business practices and is willing to spend millions on dollars on go screw yourself legal teams.

So, yes, you could theoretically get in trouble. But you are not likely to, and anyone suggesting otherwise probably has an ulterior motive.