If you don't actually want to stop, then these opportunities for pause do nothing, because in that pause you reaffirm that you do want to continue the behaviour.
This ties into why addiction is so powerful, while many people know their addictions are bad, they enjoy them and don't actually want to stop. I.E. They don't value the results of cessation versus keeping the addiction.
It's entirely possible to reach for your phone, then tap an app or load a website on your computer while being semi-aware of your actions, and this is typical for people with ingrained behaviours. These people can start scrolling instagram or twitter without really thinking about it. Having a forced circuit breaker gives these people an opportunity to stop and reconsider their actions.
At the end of the day only you have full agency over yourself.
These systems are trivial to defeat, after all you turned them on, you can just as easily turn them off, but that's not the point at all. It's not meant to be an unsurmountable technical wall. The point is to provide you with a moment to actively think about your actions instead of an autopiloting behaviour that lands you on a website or app that you are trying to avoid using. People who use employ these types of "circuit breakers" do so because they find that they frequently find themselves autopiloting to these services. For these people the circuit breaker is their moment to realise "oh hang on I said I don't want to be doing this while I'm working on my project", rather than "oh this is inconvenient, I'll just disable it for the time being".
The stopping power comes from you, not from the crutch.
