It's not about the usefulness... it's that omnipotent surveillance creates a jarring imbalance of power between the surveillance state and the people.

If the employees of the state were subject to the same exact surveillance, then maybe it might be palatable.

Curiously, the Star Trek Universe exists in such a scenario. A common trope is asking the computer for evidence of a crime, where someone is at any time, etc. I've never heard complaints about this supposed contradiction between the utopia vision of Star Trek and the omnipotent, all-seeing computer.

But we all know the reality... a tale as old as time. The state will exclude themselves from the surveillance, and it will eventually be used as a tool for authoritarianism. It's only a matter of time with something as powerful as this.