Most firealarms I know have a button that switches of the activated sound when longpressed. I also do not know smoke detectors without removable battery (outside of wired ones).
A deactivation button is different from an power switch where the thing is off when the switch is in the wrong position. And if you don't notice people die. I didn't check the ISO norms on smoke detectors but I would be surprised if power switches wouldn't be explicitly forbidden in those norms.
And sure you can get a detector that doesn't conform to the norm, but then the insurance won't pay in case of a fire.
A deactivation button is different from an power switch where the thing is off when the switch is in the wrong position. And if you don't notice people die. I didn't check the ISO norms on smoke detectors but I would be surprised if power switches wouldn't be explicitly forbidden in those norms.
And sure you can get a detector that doesn't conform to the norm, but then the insurance won't pay in case of a fire.